GNFAC Advisory Podcast https://www.mtavalanche.com/advisory/feed The daily Avalanche Advisory issued by the Gallatin National Forest Avalanche Center. en GNFAC Avalanche Advisory for Wed May 2, 2018 https://www.mtavalanche.com/advisory/18/05/02 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Wed May 2, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/1183" typeof="schema:Person" property="schema:name" datatype="">Alex Marienthal</span></span> <span class="field field--name-created field--type-created field--label-hidden">Wed, 05/02/2018 - 10:52</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>This is spring snowpack information and travel advice issued Wednesday, May 2<sup>nd</sup> 2018 and does not expire. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. Traveling in the backcountry requires careful snowpack and terrain evaluation. Avalanches don’t end until the snow melts.</p></div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter (<a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area"><strong>graphic</strong></a>) with more spring snow to come will make avalanches possible well into summer.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snowstorms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <a href="https://youtu.be/Bm9pfuscLMU"><strong>video</strong></a><strong>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p> <h3><strong>Share your observations with us! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3><strong>Info and Announcements</strong></h3> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>Bridger Bowl is closed for the season and backcountry avalanche conditions exist.</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>Have a safe and enjoyable spring and summer. See you when the flakes start to fly next Fall! -Doug, Eric, and Alex</p></div> </div> </div> </div> Wed, 02 May 2018 16:52:38 +0000 Alex Marienthal 18892 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Mon Apr 30, 2018 https://www.mtavalanche.com/advisory/18/04/30 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Mon Apr 30, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/1183" typeof="schema:Person" property="schema:name" datatype="">Alex Marienthal</span></span> <span class="field field--name-created field--type-created field--label-hidden">Mon, 04/30/2018 - 06:49</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Alex Marienthal with spring snowpack and weather information on Monday, April 30<sup>th</sup> at 7:15 a.m. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. This is our final spring weather and snowpack update for the season. Our website will be updated on Wednesday with a general spring travel and snowpack statement.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>On Friday and Saturday, temperatures in the mountains reached 60 F under mostly clear skies and overnight lows were mid to high 30s F. Over the past 24 hours the mountains received scattered rain showers and an inch or two of snow last night. Wind has been southwest to southeast at 5-10 mph and temperatures this morning are mid-20s to low 30s F. Colder and cloudier weather is forecast through the first half of the week. Temperatures will be high 20s to mid-30s F with light to moderate northerly wind. Scattered snow showers are expected daily in the mountains with 1-3” of snow possible each day through Wednesday.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>The snowpack has finally taken a leap into spring conditions. Well above freezing temperatures this weekend melted water through the snowpack on all slopes except the highest, shady aspects (due north, above ~9,500'). Cold temperatures overnight refroze the snowpack solid and stable this morning. During the melt over the weekend, large natural wet loose avalanches and a few wet slabs occurred (<strong><a href="https://www.mtavalanche.com/images/18/wet-loose-avalanches-0">photo</a></strong>, <strong><a href="https://www.mtavalanche.com/images/18/wet-slab-n-bridgers">photo</a></strong>, <strong><a href="https://www.mtavalanche.com/images/18/small-wet-slab-n-bridgers">photo</a></strong>). Colder temperatures and less sunshine the next few days will keep the snowpack mostly frozen and minimize larger wet slides like those observed over the weekend. Avalanche activity will mostly be confined to new snow that falls, or shallow wet slides if there is sunshine, rain or above freezing temperatures. See our general spring travel advice and avalanche information below.</p> <h3><strong>Give Big Gallatin Valley this Thursday and Friday!!!</strong></h3> <p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p> <h3><strong>Share your observations with us on Instagram! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3><strong>Info and Announcements</strong></h3> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>Bridger Bowl is closed for the season and backcountry avalanche conditions exist.</p> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p> <h3><strong>General Spring Snowpack and Travel Advice</strong></h3> <p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter (<a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area"><strong>graphic</strong></a>) with more spring snow to come will make avalanches possible well into summer.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snowstorms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <a href="https://youtu.be/Bm9pfuscLMU"><strong>video</strong></a><strong>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p></div> </div> </div> </div> Mon, 30 Apr 2018 12:49:22 +0000 Alex Marienthal 18888 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Fri Apr 27, 2018 https://www.mtavalanche.com/advisory/18/04/27 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Fri Apr 27, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/1183" typeof="schema:Person" property="schema:name" datatype="">Alex Marienthal</span></span> <span class="field field--name-created field--type-created field--label-hidden">Fri, 04/27/2018 - 05:36</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Alex Marienthal with spring snowpack and weather information on Friday, April 27<sup>th</sup> at 6:00 a.m. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. This information will be updated Monday morning. Bridger Bowl is closed for the season and backcountry conditions exist.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>Temperatures this morning are low to mid-30s F and wind is southerly at 5-10 mph. The mountains have not received any new snow since Monday. Today will be clear with temperatures reaching high 50s F and easterly wind at 5-15 mph. Temperatures will remain above freezing tonight and tomorrow, and wind will shift to southwest at 10-20 mph. A cold front Saturday night will bring rain, followed by snow through Monday. Expect precipitation totals between 0.5 and 1” of water equivalent with 3-5” of snow possible in the mountains south of Bozeman by Monday.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>Well above freezing temperatures will make wet avalanches possible today, and wet loose and wet <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches may become more likely this weekend (<strong><a href="https://www.mtavalanche.com/images/18/wet-slide-debris">photo</a></strong>, <strong><a href="https://www.mtavalanche.com/images/18/natural-slab-avalanche">photo</a></strong>). A quick spring storm last Monday deposited 12-18” of heavy snow throughout the mountains. Since then, sunny, warm spring days and below freezing temperatures overnight have made the snowpack melt and refreeze on all but high northerly facing slopes.</p> <p>Near freezing temperatures and clear skies last night create a frozen and stable snowpack this morning. As temperatures warm above freezing and slopes receive direct sunlight today, the snowpack will melt and lose strength, and wet snow avalanches will become more likely. Above freezing temperatures are forecast tonight, which will make the snowpack start wet and unstable tomorrow morning. Rain up to 9,000 feet is possible late Saturday and Sunday morning. Heavy rain on a wet snowpack can create large wet <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches.</p> <p>Avoid travel on steep slopes and be aware of potential avalanche terrain overhead if the snowpack is wet and unsupportive, or if there is heavy rain. Wet snow avalanches could be large, destructive and run long distances. Hit the trail early and finish early before the snowpack melts and weakens. If the snowpack didn’t freeze overnight, find alternate plans (e.g., fishing, climbing) or find slopes with more stable snow. Cornices will lose strength with warm temperatures and become easier to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or break naturally (<strong><a href="https://www.mtavalanche.com/images/18/crack-large-cornice">photo</a></strong>, <strong><a href="https://www.mtavalanche.com/images/18/rows-cornices">photo</a></strong>). See general spring travel advice and avalanche information below.</p> <h3><strong>Share your observations with us on Instagram! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p> <div> <hr /></div> <p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter (<a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area"><strong>graphic</strong></a>) with more spring snow to come will make avalanches possible well into summer.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snowstorms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <a href="https://youtu.be/Bm9pfuscLMU"><strong>video</strong></a><strong>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3>Info and Announcements</h3> <p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>On April 12, 2018, <a href="https://www.mtavalanche.com/weather/stations/fischer-creek"><strong>Fisher Creek SNOTEL</strong></a> reached its most SWE on record for one season!!!</p> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p></div> </div> </div> </div> Fri, 27 Apr 2018 11:36:18 +0000 Alex Marienthal 18882 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Mon Apr 23, 2018 https://www.mtavalanche.com/advisory/18/04/23 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Mon Apr 23, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/1183" typeof="schema:Person" property="schema:name" datatype="">Alex Marienthal</span></span> <span class="field field--name-created field--type-created field--label-hidden">Mon, 04/23/2018 - 06:55</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Alex Marienthal with spring snowpack and weather information on Monday, April 23<sup>rd</sup> at 7:00 a.m. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. This information will be updated Friday morning. Bridger Bowl is closed for the season and backcountry conditions exist.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>At 5 a.m. the Bridger Range has 12” of heavy new snow and the mountains near Big Sky have 8”. SNOTEL is not reporting data elsewhere, but webcams show new snow in Cooke City and West Yellowstone (<strong><a href="https://www.mtavalanche.com/images/18/new-snow-cooke-23-apr">photo</a></strong>). Temperatures are 20s F this morning and will reach mid-30s F today. Wind will be northeast at 15-25 mph. Snow showers are expected through this afternoon and the mountains could get 4-6” today.</p> <p>Tuesday will be mostly clear with temperatures in the 40s F. There is a chance for light precipitation Wednesday evening, and the rest of the week will be mostly sunny with highs in the 40s F and overnight lows in the 20s F. Snow and rain appear in the forecast again next weekend.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>Heavy new snow will be unstable and create dangerous avalanche conditions today and the next few days. Last night the mountains got 8-12” of snow equal to .8-1.2” of <a href="http://www.or.nrcs.usda.gov/snow/about/swe.html">snow water equivalent</a> (SWE), and more is expected today. Avalanches in the new snow are likely today. They will be deeper and easier to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> on wind-loaded slopes, but likely and dangerous on all steep slopes. Wind loaded slopes and slopes steeper than 35 degrees should be avoided today, and approached with extra caution for the next few days.</p> <p>Above freezing temperatures and sunshine after the storm will make wet snow avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> and run naturally. These will be large and run long distances. Be aware of steep terrain above you as temperatures warm through the day, or when the sun comes out. Avoid steep slopes if you see signs of instability like natural avalanches, pinwheels of snow, or the surface becomes wet. Conditions will change rapidly the next few days, and become more stable toward the end of the week. See our general spring travel advice and avalanche information below.</p> <h3><strong>Share your observations with us on Instagram! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p> <div> <hr /></div> <p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter (<a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area"><strong>graphic</strong></a>) with more spring snow to come will make avalanches possible well into summer.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snowstorms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <a href="https://youtu.be/Bm9pfuscLMU"><strong>video</strong></a><strong>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3>Info and Announcements</h3> <p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>On April 12, 2018, <a href="https://www.mtavalanche.com/weather/stations/fischer-creek"><strong>Fisher Creek SNOTEL</strong></a> reached its most SWE on record for one season!!!</p> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p></div> </div> </div> </div> Mon, 23 Apr 2018 12:55:57 +0000 Alex Marienthal 18873 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Fri Apr 20, 2018 https://www.mtavalanche.com/advisory/18/04/20 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Fri Apr 20, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/126" typeof="schema:Person" property="schema:name" datatype="">Eric Knoff</span></span> <span class="field field--name-created field--type-created field--label-hidden">Fri, 04/20/2018 - 06:37</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Eric Knoff with spring snowpack and weather information on Friday, April 20<sup>th </sup>at 6:45 a.m. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. This information will be updated Monday morning. This bulletin does not apply to operating ski areas. Bridger Bowl is closed for the season and backcountry conditions exist.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>It’s hard to imagine, but the next few days will be sunny and warm. Highs today and through the weekend will reach the mid to upper 40’s F in the mountains and 50’s to 60’s in the valley. Lows will be in the 20s’ F. Winds will remain light to moderate out of west-southwest. There is little to no chance of precipitation the next few days. The next chance for rain and snow will be Monday and Tuesday.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>For the first time all season, snotel sites across the advisory area lost SWE (snow water equivalent). This is a key indicator the snowpack is starting a well overdue transition to a warmer and wetter spring pack. This also means that free moving water is being introduced, which can create unstable conditions. Fortunately, temperatures dropped below freezing overnight, which helps slow the melting process and reduce rapid disintegration of the snowpack.</p> <p>Today, <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will be fairly predictable. All but the highest north facing slopes will have a firm melt-freeze crust, which will create terrible riding conditions but good <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> during the morning hours. As the day progresses, conditions will soften and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will gradually decrease.</p> <p>Slopes facing the south half of the compass will destabilize first. This will transition to east, west and eventually north facing slopes by the afternoon hours. Watch for pinwheels and small sluffs moving in steeper terrain. These are clues the snowpack is losing strength. If signs of instability are observed including soft-wet snow more than boot top deep, it’s time to move away from steep slopes or to shadier aspects.</p> <p>Cornices are also a significant hazard (<strong><a href="https://www.mtavalanche.com/images/18/large-cornice-n-madison-range">photo</a></strong>). As temps warm above freezing, these overhanging masses of snow will become increasingly unstable. They can break farther back than you might expect and <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> large avalanches on the slopes below.</p> <p>If you have not done so already, check out our spring avalanche advice below.</p> <h3><strong>Share your observations with us on Instagram! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p> <div> <hr /></div> <p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. A deep snowpack in the mountains will make avalanches possible for the next few months. Continue to assess the snowpack, weather, and terrain carefully and practice safe travel techniques for the remainder of the season.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snow storms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3>Info and Announcements</h3> <p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>On April 12, 2018, <a href="https://www.mtavalanche.com/weather/stations/fischer-creek"><strong>Fisher Creek SNOTEL</strong></a> reached its most SWE on record for one season!!!</p> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p></div> </div> </div> </div> Fri, 20 Apr 2018 12:37:34 +0000 Eric Knoff 18867 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Mon Apr 16, 2018 https://www.mtavalanche.com/advisory/18/04/16 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Mon Apr 16, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/126" typeof="schema:Person" property="schema:name" datatype="">Eric Knoff</span></span> <span class="field field--name-created field--type-created field--label-hidden">Mon, 04/16/2018 - 06:30</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Eric Knoff with spring snowpack and weather information on Monday, April 16<sup>th </sup>at 6:45 a.m. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. We will update weather and snowpack information every Monday and Friday for most of April. I will update this information Friday morning. This bulletin does not apply to operating ski areas. Bridger Bowl is closed for the season and backcountry conditions exist.</p> <h3><strong>Avalanche Fatality</strong></h3> <p>On Saturday, April 14<sup>th</sup> at approximately 10:30 a.m., a solo skier exited the south boundary of Bridger Bowl Ski Resort and hiked to the summit of Saddle Peak (elevation 9,100 feet). Around 10:50 a.m., the skier dropped off the summit of Saddle Peak and triggered the avalanche. He was caught and carried 1,500 vertical feet down a steep and narrow <a href="https://staging.avalanche.org/avalanche-education/avalanche-path" title="A terrain feature where an avalanche occurs. Composed of a Starting Zone, Track, and Runout Zone." class="taxonomy-tooltip-link" target="_blank">avalanche path</a>. The victim was buried with his hand sticking out of the snow.</p> <p>At the time of the <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a>, a skier riding Schlashman's Chairlift at Bridger Bowl Ski Resort witnessed the skier <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> and get caught in the avalanche. The witness was unsure if the skier escaped the avalanche, but informed ski patrol at the top of the lift. Members of ski patrol called Gallatin County Search and Rescue to inform them of the incident and mobilized for a search.</p> <p>Approximately one hour later, members of the Bridger Bowl Ski Patrol located the buried victim. CPR was performed, but resuscitation efforts were unsuccessful. The skier was wearing an avalanche beacon, but had no partner. The avalanche is classified as SS-AS-R3-D2-I</p> <p>You can view photos of the incident <a href="https://www.mtavalanche.com/photos"><strong>here</strong></a>. Our condolences go out the victim’s friends and family.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>There is no new snow to report over the past 24 hours. This morning skies are mostly clear and temps range from the upper 20’s to mid-30’s F. Winds are blowing 15-30 mph out of the SW with gusts around Hyalite and Big Sky breaking 50 mph. Today, skies will become increasingly cloudy as a cold front approaches the region. Valley rain and mountain snow are likely this afternoon with the frontal passage. There’s also the possibility of a thunderstorm. The mountains south of Bozeman will see 2-4” by tomorrow morning while the Bridger Range will see 1-3”. Highs today will climb to the upper 30’s to low 40’s before the cold front reaches the area. Winds will remain moderate to strong out of the SW. Winds will shift to the W-NW behind the front. Cloudy skies and cooler temps will remain over the region through Wednesday.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>Below average temperatures and above average precipitation this spring has kept the snowpack cold and dry. Typically, the pack has undergone multiple freeze-thaw cycles and is well on its way to becoming a warmer and wetter spring pack by now. That is not the case this year.</p> <p>The avalanche fatality on Saddle Peak this past Saturday is a somber reminder that avalanche season is far from over (<a href="https://www.youtube.com/watch?v=p_TrWEmHkVU"><strong>video</strong></a>, <a href="https://www.mtavalanche.com/photos"><strong>photos</strong></a>). Snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> is complicated this time of year and conditions can change very quickly. Sun, snow, rain, gusty winds, and rapidly warming temperatures are all factors in the spring. It is not uncommon to have a wide variety of conditions in a single day, especially in Montana. Anticipate rapidly changing conditions and plan accordingly.</p> <p>With more snow and wind in the forecast, wind slabs and dry loose avalanches will be the primary avalanche problems to keep an eye out for. Wet loose avalanches will also be possible if it rains or if the sun shines for an extended period of time (<strong><a href="https://www.mtavalanche.com/images/18/wet-loose-avalanche-bridger-bowl">photo</a></strong>) – however, this problem should be short lived as cooler temps, snow and wind are in the forecast for the middle of the week. Also, watch for and avoid large cornices along the ridgelines.</p> <p>If you have not done so already, check out our spring avalanche advice below.</p> <p><strong>Share your observations with us on Instagram! #gnfacobs</strong></p> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p> <div> <hr /></div> <p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Heavy snow in the mountains (<a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area"><strong>graphic</strong></a>) will make avalanches possible for the next few months. Continue to assess the snowpack, weather, and terrain carefully and practice safe travel techniques for the remainder of the season.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snow storms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <a href="https://youtu.be/Bm9pfuscLMU"><strong>video</strong></a><strong>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3>Info and Announcements</h3> <p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>On April 12, 2018, <a href="https://www.mtavalanche.com/weather/stations/fischer-creek"><strong>Fisher Creek SNOTEL</strong></a> reached its most SWE on record for one season!!!</p> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p></div> </div> </div> </div> Mon, 16 Apr 2018 12:30:07 +0000 Eric Knoff 18856 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Sun Apr 15, 2018 https://www.mtavalanche.com/advisory/18/04/15 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Sun Apr 15, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/124" typeof="schema:Person" property="schema:name" datatype="">Doug Chabot</span></span> <span class="field field--name-created field--type-created field--label-hidden">Sun, 04/15/2018 - 06:02</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Doug Chabot with spring snowpack and weather information on Sunday, April 15<sup>th </sup>at 6:45 a.m. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. We will update weather and snowpack information every Monday and Friday for most of April. Eric will update this information tomorrow morning. This bulletin does not apply to operating ski areas.</p> <h3><strong>Avalanche Fatality</strong></h3> <p>Yesterday morning a solo skier triggered an avalanche descending off the north summit of Saddle Peak. A few hundred feet from the top he triggered an avalanche that broke 1-3’ deep, 100’ wide, and carried him 1500’ vertical distance down the narrow path. Our investigation at the crown revealed dense wind-drifted snow resting on a thin ice crust (the <a href="https://staging.avalanche.org/avalanche-education/bed-surface" title="The surface over which a fracture and subsequent avalanche release occurs. Can be either the ground or a snow surface." class="taxonomy-tooltip-link" target="_blank">bed surface</a>). Skiers on a chairlift at Bridger Bowl witnessed the <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> and alerted the ski patrol who then responded as volunteers for Gallatin County Search and Rescue (GCSAR). Three patrollers climbed Saddle Peak and descend the slope picking up a beacon signal near the toe of the debris. The victim’s gloved hand was sticking out of the snow and the rescuers were able to reach his head quickly. Resuscitation efforts were not successful. Approximately 75 minutes elapsed from the avalanche to extrication. I visited the scene yesterday afternoon and will have more information later today and a full report early in the week.</p> <p>All of us at the avalanche center are deeply saddened by this accident. The skier was known to many and we offer our sincere condolences to his friends and family.</p> <p>Four photos of the avalanche are posted <strong><a href="https://www.mtavalanche.com/photos">HERE</a> </strong>with more being uploaded later today.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>In the last 24 hours the mountains around West Yellowstone picked up 2” of snow, with up to an inch falling in other areas. This morning is mostly cloudy with winds 10-25 mph out of the southwest, and a freezing line of 7,000’. Mountain temperatures will rise into the 40s F this afternoon. Scattered precipitation today will drop rain or snow (1-2”) depending on the elevation. Thunderstorms are likely. Tonight will be below freezing and winds will shift to the southeast.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>Yesterday’s avalanche fatality should give us pause, no matter where we ski or ride. Since Wednesday the Bridger Range has received almost 5” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2_046155">snow water equivalent</a> (40” of snow) while other areas have gotten upwards of 2.5” of SWE. This is a lot of weight and many slopes avalanched naturally on Friday. Winds created thick slabs and also grew cornices even bigger (<strong><a href="https://www.mtavalanche.com/images/18/cornices-and-crown">photo</a></strong>). A few feet of new snow and wind-<a href="https://staging.avalanche.org/avalanche-education/loading" title="The addition of weight on top of a snowpack, usually from precipitation, wind drifting, or a person." class="taxonomy-tooltip-link" target="_blank">loading</a> since Wednesday, natural avalanches on Friday, a skier fatality on Saturday, are all red flags. Avalanches in this new snow are still possible today, especially if the snow is resting on an ice crust.</p> <p>Snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> is not simple this time of year and I expect a lot of changes to occur in the snowpack today, especially if it rains. Rain quickly creates unstable conditions. Snow, rain, gusty winds, and thunderstorms are all on the menu. Dry avalanches could be triggered in the morning, especially on wind-loaded slopes, and wet avalanches in the afternoon. We need to keep our thinking and decision-making nimble with rapidly changing conditions.</p> <p>If you have not done so already, check out our spring avalanche advice below.</p> <h3><strong>Share your observations with us on Instagram! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p> <div> <hr /></div> <p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter (<a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area"><strong>graphic</strong></a>) with more spring snow to come will make avalanches possible well into summer.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snow storms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <a href="https://youtu.be/Bm9pfuscLMU"><strong>video</strong></a><strong>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3>Info and Announcements</h3> <p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>On April 12, 2018, <a href="https://www.mtavalanche.com/weather/stations/fischer-creek"><strong>Fisher Creek SNOTEL</strong></a> reached its most SWE on record for one season!!!</p> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p></div> </div> </div> </div> Sun, 15 Apr 2018 12:02:54 +0000 Doug Chabot 18844 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Sat Apr 14, 2018 https://www.mtavalanche.com/advisory/18/04/14 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Sat Apr 14, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/124" typeof="schema:Person" property="schema:name" datatype="">Doug Chabot</span></span> <span class="field field--name-created field--type-created field--label-hidden">Sat, 04/14/2018 - 06:27</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Doug Chabot with spring snowpack and weather information on Saturday, April 14<sup>th </sup>at 6:45 a.m. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. We will update weather and snowpack information every Monday and Friday for most of April. Eric will update this information Monday morning. This bulletin does not apply to operating ski areas.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>Another 1-2” of snow fell yesterday. At 5 a.m. skies are partly cloudy, temperatures are in the high teens to low 20s F, and winds are westerly at 15-30 mph. The weekend will be mostly cloudy with daytime highs reaching the 40s today and near 50 F tomorrow. Scattered snow showers will drop another 2-4” by Monday morning as winds shift southwest at 20 mph.</p> <p>Winter will keep us hostage through next week, maybe longer, as Spring negotiates our release. Below average temperatures and above average precipitation remains on <a href="https://staging.avalanche.org/avalanche-education/track" title="The portion of an avalanche path between the starting zone and the runout zone." class="taxonomy-tooltip-link" target="_blank">track</a> for the rest of April.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>Yesterday we issued an Avalanche Warning in the Bridger Range after 30” of snow fell. The Bridger Bowl ski patrol reported many large slides breaking trees and running long distances. At Big Sky large avalanches were triggered by ski patrol in the 1-2’ of new snow. The patrol also noted a large natural <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> on the NE face of Fan Mountain that was likely triggered by a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> fall. Avalanche debris from new snow slides will be seen around Cooke City, West Yellowstone and the southern ranges from the 16-24” of snow that fell since Wednesday. The new snow will stabilize quickly, but triggering sluffs or wind slabs are possible through the weekend.</p> <p>Winds have died down and temperatures will warm into the 40s F. Complicating matters, the new snow will provide ammunition for wet avalanches. Direct sunshine will turn dry snow wet head-spinning fast. Roller balls, pinwheels and loose snow avalanches are signs that the avalanche danger is getting worse.</p> <p>The weekend will be much safer than Friday, but avalanches are still possible. Expect dry, new snow avalanches in the morning and possibly wet avalanches in the afternoon. <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">Stability</a> changes rapidly in the spring. You made it this far, so don’t blow it now. See our general spring travel advice below.</p> <h3><strong>Share your observations with us on Instagram! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p> <div> <hr /></div> <h3>Spring Weather Information</h3> <p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter (<a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area"><strong>graphic</strong></a>) with more spring snow to come will make avalanches possible well into summer.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snow storms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <a href="https://youtu.be/Bm9pfuscLMU"><strong>video</strong></a><strong>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3>Info and Announcements</h3> <p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>On April 12, 2018, <a href="https://www.mtavalanche.com/weather/stations/fischer-creek"><strong>Fisher Creek SNOTEL</strong></a> reached its most SWE on record for one season!!!</p> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local nonprofits.</p></div> </div> </div> </div> Sat, 14 Apr 2018 12:27:47 +0000 Doug Chabot 18837 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Fri Apr 13, 2018 https://www.mtavalanche.com/advisory/18/04/13 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Fri Apr 13, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/1183" typeof="schema:Person" property="schema:name" datatype="">Alex Marienthal</span></span> <span class="field field--name-created field--type-created field--label-hidden">Fri, 04/13/2018 - 06:56</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Alex Marienthal with spring snowpack and weather information on Friday, April 13<sup>th </sup>at 7:00 a.m. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. We will update this bulletin tomorrow morning. This bulletin does not apply to operating ski areas.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>Winter is here. Still here. A major spring storm ends this morning, and over the last 24 hours it dumped 20-30" in the Bridger Range, 14-20” in Hyalite and Big Sky, and 6-9” near West Yellowstone and Cooke City. Wind overnight was west to northwest at 15-25 mph with gusts of 30-45 mph. This morning, temperatures range from low teens to mid-20s F, and will be 20s to low 30s F today. Snowfall tapers off this morning with another 2-3” possible.</p> <p>This weekend will be mostly cloudy with a few periods of sunshine possible and temperatures in the 30s to low 40s F. Light snow showers Saturday and Sunday evenings could drop 2-4” with more expected late Monday to Tuesday.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group warning" > <div class = "region hazard-rating-image" ><a href ="#" title = "High Avalanche Hazard" alt ="High Avalanche Hazard"><img src ="/images/hazard_ratings/simple/High.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" ><a href="/advisory/bridgers" class="advisory-region" style="color: #fafafa;">Bridger Range</a></h3></div><h3 class = "warning" >Avalanche Warning</h3><p>Very dangerous avalanche conditions exist in the Bridger Range. Bridger Bowl got 30" of snow equal to 2.5" of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2_046155">snow water equivalent</a> over the last 24 hours. Ski patrol was up early and reported large natural avalanches that ran long distances. Natural and human triggered avalanches are likely today and all avalanche terrain should be avoided. Avalanche Danger is rated <a href = "/images/DangerScale-small.jpg" class ="colorbox "><span style = "background-color: #ee1d23; font-weight: bolder;"><span class = "avayhzrd-high">HIGH</span></span></a> on all slopes.</p><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" ><a href="/advisory/northern-gallatin" class="advisory-region" style="color: #fafafa;">Gallatin Range</a></h3><h3 class ="region" ><a href="/advisory/northern-madison" class="advisory-region" style="color: #fafafa;">Madison Range</a></h3><h3 class ="region" ><a href="/advisory/bridgers" class="advisory-region" style="color: #fafafa;">Lionhead Range</a></h3><h3 class ="region" ><a href="/advisory/cooke-city" class="advisory-region" style="color: #fafafa;">Cooke City</a></h3></div><p>Since Wednesday morning, the mountains received 16-24” of snow equal to 1.5-2.5” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2_046155">snow water equivalent</a> (SWE). Dangerous avalanche conditions exist today, and recent heavy snow will create serious avalanche hazards through the weekend. Today, slabs or loose avalanches of new snow are likely for a person to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a>, and natural avalanches are possible. Avalanches will be more reactive or break naturally where wind overnight and today drifts snow into deeper slabs. The recent snow is a lot of weight and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> tests could be untrustworthy. Avalanche terrain should be avoided today, especially where wind loaded.</p> <p>This weekend, cautious route finding and conservative terrain selection are essential. Be cautious of steep slopes and wind-loaded terrain. Avalanches will remain possible and large enough to bury a person, or powerful enough to carry someone through trees or over cliffs. Similar to this <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> triggered near Cooke City last Monday (<strong><a href="https://www.mtavalanche.com/images/18/snowmobile-triggered-slide-lulu-pass">photo</a></strong>). Be cautious of steep terrain above you, where large natural wet avalanches could release as the recent snow warms up with sun and above freezing temperatures. New snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> changes rapidly in the spring. See our general spring travel advice below.</p> <hr /> <p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter (<a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area"><strong>graphic</strong></a>) with more spring snow to come will make avalanches possible well into summer.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snowstorms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change terrain and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row.</p> <p>Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <a href="https://youtu.be/Bm9pfuscLMU"><strong>video</strong></a><strong>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p> <h3><strong>Share your observations with us on Instagram! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3>Info and Announcements</h3> <p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local non-profits.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p> <p>Yesterday morning (April 12, 2018), <strong><a href="https://www.mtavalanche.com/weather/stations/fischer-creek">Fisher Creek SNOTEL</a></strong> reached its most SWE on record for one season!!!</p> <p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p> <div> <hr /></div></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>May 3-4<sup>th</sup>, <a href="https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center"><strong>Give Big</strong></a> online fundraising campaign! A 24-hour fund-raising campaign for the Friends of the Avalanche Center and other local non-profits.</p></div> </div> </div> </div> Fri, 13 Apr 2018 12:56:32 +0000 Alex Marienthal 18835 at https://www.mtavalanche.com GNFAC Avalanche Advisory for Mon Apr 9, 2018 https://www.mtavalanche.com/advisory/18/04/09 <span class="field field--name-title field--type-string field--label-hidden">GNFAC Avalanche Advisory for Mon Apr 9, 2018</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="/user/1183" typeof="schema:Person" property="schema:name" datatype="">Alex Marienthal</span></span> <span class="field field--name-created field--type-created field--label-hidden">Mon, 04/09/2018 - 06:46</span> <div class="layout layout--onecol"> <div class="layout__region layout__region--content"> <div class="clearfix text-formatted field field--name-field-intro field--type-text-long field--label-hidden field__item"><p>Good Morning. This is Alex Marienthal with spring snowpack and weather information on Monday, April 9<sup>th</sup>. The Gallatin National Forest Avalanche Center has stopped issuing daily avalanche advisories for the season. We will issue weather and snowpack updates on Monday and Friday mornings for most of April. This bulletin does not apply to operating ski areas.</p></div> <div class="clearfix text-formatted field field--name-field-weather field--type-text-long field--label-above"> <div class="field__label">Mountain Weather</div> <div class="field__item"><p>Since yesterday morning the mountains got 3-5” of new snow. This morning, temperatures are teens to mid-20s F and wind is west to northwest at 15-25 mph. Temperatures will reach high 30s F today with west to northwest wind at 10-20 mph. Today and tomorrow will be partly cloudy with no precipitation expected, and temperatures tomorrow in the mid-40s F. Cloud cover will increase tomorrow afternoon with 2-3” of snow expected Wednesday morning and more snow likely Wednesday night through Thursday.</p> <div class="full-weather-wrapper "><ul class="full-weather button-list"><li><a href="/weather/wx-avalanche-log">Weather and Avalanche Log</a></li></ul></div></div> </div> <div class="discussion"><div class="field__label">Snowpack and Avalanche Discussion</div><div class = "region-group" > <div class = "region hazard-rating-image" ><a href ="#" title = "None Avalanche Hazard" alt ="None Avalanche Hazard"><img src ="/images/hazard_ratings/simple/None.png" class = "hazard-image-main" /></a><br /></div><h3 class ="region" >All Regions</h3></div><p>Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter (<strong><a href="https://www.mtavalanche.com/images/18/swe-snotel-sites-gnfac-area">graphic</a></strong>) with more spring snow to come will make avalanches possible well into summer.</p> <p><u>NEW SNOW AND WIND LOADED SLOPES</u></p> <p>Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snowstorms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give new snow a day to adjust before hitting big terrain. New snow instabilities can be difficult to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Wind loaded slopes and slopes steeper than 35 degrees should be avoided for 24-48 hours after new snow and wind.</p> <p>New snow can quickly change from dry to wet on a spring day, and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning, and then easily <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> as you change <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> or elevation, and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a>.</p> <p><u>WET SNOW AVALANCHES</u></p> <p>Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak, and make wet avalanches easy to <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row. Avoid steep terrain, and be aware of potential for natural wet avalanches in steep terrain above you, if you see:</p> <ul> <li>Heavy rain,</li> <li>Above freezing temperatures for more than 24 hours,</li> <li>Natural wet avalanches,</li> <li>Roller balls or pin wheels indicating a moist or wet snow surface,</li> <li>Or if you sink to your boot top in wet snow.</li> </ul> <p>In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, <a href="https://staging.avalanche.org/avalanche-education/aspect" title="The compass direction a slope faces (i.e. North, South, East, or West.)" class="taxonomy-tooltip-link" target="_blank">aspect</a> and elevation determine how fast <a href="https://staging.avalanche.org/avalanche-education/stability" title="The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human). " class="taxonomy-tooltip-link" target="_blank">stability</a> will decrease through the day. Be aware that sunny aspects may have a <a href="https://staging.avalanche.org/avalanche-education/wet-snow-avalanche" title="An avalanche caused by snow losing its strength after becoming damp, moist or saturated with water." class="taxonomy-tooltip-link" target="_blank">wet snow avalanche</a> danger while shadier slopes still have a <a href="https://staging.avalanche.org/avalanche-education/dry-snow-avalanche" title="An avalanche that occurs in snow below freezing temperatures." class="taxonomy-tooltip-link" target="_blank">dry snow avalanche</a> danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe. See Eric’s recent <strong><a href="https://youtu.be/Bm9pfuscLMU">video</a>,</strong> and this <a href="https://www.mtavalanche.com/blog/transitions-spring-snow-avalanche-problems"><strong>article</strong></a> for more spring travel advice.</p> <p><u>CORNICES</u></p> <p>Cornices along ridgelines are massive and can break under the weight of a person (<a href="https://www.mtavalanche.com/images/18/behemouth-cornices"><strong>photo</strong></a>). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">Cornice</a> falls can also entrain large amounts of loose snow or <a href="https://staging.avalanche.org/avalanche-education/trigger" title="A disturbance that initiates fracture within the weak layer causing an avalanche. In 90 percent of avalanche accidents, the victim or someone in the victims party triggers the avalanche." class="taxonomy-tooltip-link" target="_blank">trigger</a> <a href="https://staging.avalanche.org/avalanche-education/slab" title="A relatively cohesive snowpack layer." class="taxonomy-tooltip-link" target="_blank">slab</a> avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> triggers a <a href="https://staging.avalanche.org/avalanche-education/slide" title="A mass of snow sliding, tumbling, or flowing down an inclined surface. Same as avalanche." class="taxonomy-tooltip-link" target="_blank">slide</a> or not, a falling <a href="https://staging.avalanche.org/avalanche-education/cornice" title="A mass of snow deposited by the wind, often overhanging, and usually near a sharp terrain break such as a ridge. Cornices can break off unexpectedly and should be approached with caution." class="taxonomy-tooltip-link" target="_blank">cornice</a> is dangerous to anyone in its path.</p> <p><u>DISCLAIMER</u></p> <p>It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.</p> <p>Have a safe and enjoyable spring and summer!</p> <p>Doug, Eric, and Alex</p> <h3><strong>Share your observations with us on Instagram! #gnfacobs</strong></h3> <p>Posting your snowpack and avalanche observations on Instagram (#gnfacobs) is a great way to share avalanche and weather information with us and everyone else this spring.</p> <p>You can also drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a> or email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>) and we will share pertinent avalanche, weather and snowpack info as timely as possible.</p><div><ul class="button-list"><li><a href="/node/add/snow_observation">Submit Snow Observations</a></li></ul></div></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h3>Info and Announcements</h3> <p>We will issue weather and snowpack updates on Monday and Friday mornings for most of April.</p> <p>Hyalite Canyon road is closed to vehicles and reopens May 16<sup>th</sup>.</p></div> <div class="clearfix text-formatted field field--name-field-forecasters-choice-text field--type-text-long field--label-above"> <div class="field__label">The Last Word</div> <div class="field__item"><p>Sledders, mark your calendar for May 19, the <a href="https://www.mtavalanche.com/images/18/2018-spring-sled-fest"><strong>2<sup>nd</sup> Annual Sled Fest</strong></a> in Cooke City. It’s a fundraiser for the Friends of the Avalanche Center and there will be a DJ, raffle prizes and BBQ on the mountain.</p></div> </div> </div> </div> Mon, 09 Apr 2018 12:46:07 +0000 Alex Marienthal 18821 at https://www.mtavalanche.com