GNFAC Avalanche Forecast for Fri Apr 30, 2021
<p>Large wet slab avalanches are likely today and tomorrow. Temperatures are the warmest that this winter’s snowpack has felt, reaching 40s and 50s F the last few days and not dropping below freezing the last two nights. We received a report from someone who traversed the Bridger Range on Wednesday and saw multiple wet slides, some that broke a couple feet deep (<strong><a href="https://www.mtavalanche.com/node/24881">photos and details</a></strong>). As temperatures reach 60s F today, large wet snow avalanches will occur naturally, and will be easy to trigger if you travel on steep, snow-covered slopes. On Saturday afternoon, any steady rain in the mountains could trigger wet snow avalanches. Wet slides could remain possible to trigger on Sunday if the snowpack does not freeze Saturday night.</p>
<p>The weak, unconsolidated snowpack creates poor skiing and riding conditions and difficult travel. Don’t fight it, winter will return on Sunday. During these summer-like days while the deep, recently dry snowpack melts, consider off-snow activities or limit travel to low angle slopes. Get the bike out, maybe hit the river or crag. Regardless of your activity, minimize time spent underneath steep, snowy slopes even if the ground under your feet is dry.</p>
<p>Sunday and next week, conditions will be more appropriate for skis or a snowmobile. The snowpack will freeze most nights and avalanche concerns will involve new snow that falls, or small wet slides as the snow surface melts through each day. Avalanches will continue until the snowpack has melted. Remain diligent with careful snowpack assessment and cautious terrain selection. See below for additional general spring snowpack and travel advice.</p>
<p>Continue to share your avalanche observations. We will post them on our website/media to help each other stay safe. Thank you for your support and see you next fall. You can submit observations via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Give Big Gallatin Valley
Give Big Gallatin Valley is May 6th –7th. The Friends of the Avalanche Center are participating again this year and want to thank all of you for your support.
Natural wet slides in Bridger Range, 4/26-4/28
From obs: "I traversed the Bridger range yesterday (4/28/21). The alpine start was good and solid but I saw lots of recent avalanches that looked super wet, some that had broken a couple feet deep. Conditions were pretty stable until about 1300 when that most recent snow layer started to really want to slide on the crust. Once I was in the meadows between Baldy and the M, at about 1400, I started hearing/feeling really wet "whumps".
From obs: "I traversed the Bridger range yesterday (4/28/21). The alpine start was good and solid but I saw lots of recent avalanches that looked super wet, some that had broken a couple feet deep. Conditions were pretty stable until about 1300 when that most recent snow layer started to really want to slide on the crust. Once I was in the meadows between Baldy and the M, at about 1400, I started hearing/feeling really wet "whumps". Photo: J. Harrison
Forecast link: GNFAC Avalanche Forecast for Fri Apr 30, 2021
From obs: "I traversed the Bridger range yesterday (4/28/21). The alpine start was good and solid but I saw lots of recent avalanches that looked super wet, some that had broken a couple feet deep. Conditions were pretty stable until about 1300 when that most recent snow layer started to really want to slide on the crust. Once I was in the meadows between Baldy and the M, at about 1400, I started hearing/feeling really wet "whumps". Photo: J. Harrison
Forecast link: GNFAC Avalanche Forecast for Fri Apr 30, 2021GNFAC Avalanche Forecast for Mon May 3, 2021
Weather and Avalanche Log for Fri Apr 30, 2021
Overnight temps 40 F at 8,000-9,500'. 50-60 F at 6,000-7,500'.
Weather and Avalanche Log for Thu Apr 29, 2021
Overnight temps >0C below 8,000' elev.
Natural wet loose slides in Absarokas
From obs 4/28/21: "Observed numerous natural wet loose slides probably occurring over the past 48 hours on NW-W-S aspects mid-elevation. Point releases from rock bands and couloirs shedding. Photo for example, which shows W facing bowl with slides visible from US-89 in Paradise Valley. These are between 8500’ and 9500’ on an unnamed peak just northeast of Dexter Point."
From obs 4/28/21: "Observed numerous natural wet loose slides probably occurring over the past 48 hours on NW-W-S aspects mid-elevation. Point releases from rock bands and couloirs shedding. Photo for example, which shows W facing bowl with slides visible from US-89 in Paradise Valley. These are between 8500’ and 9500’ on an unnamed peak just northeast of Dexter Point." Photo: T. Benson
Absaroka, greater Mill Creek region between 8500’ and 9500’...
Observed numerous natural wet loose slides probably occurring over the past 48 hours on NW-W-S aspects mid-elevation. Point releases from rock bands and couloirs shedding. Photo for example, which shows W facing bowl with slides visible from US-89 in Paradise Valley. These are between 8500’ and 9500’ on an unnamed peak just northeast of Dexter Point. Nothing crazy just thought I’d pass along.
Ross Peak/ Banana Couloir
This morning we toured up Ross Peak to check out the effects of the heat and sun these past few days. On our ascent, we observed the potential for wet slabs on an eastern aspect through a series of hand shear tests (photo). The top most layer displayed a Q1 shear quality with medium effort. To the north, we observed a natural wet slab on a southern aspect (photo). Runnels were widespread in the area, and observed on southern to northeastern aspects (photo). We found a breakable sun crust above the recent snow on eastern and north eastern aspects. In the Banana, we observed debris from wet loose releases off the cliff face that travelled far down the southern face (photo). We were travelling in this area before temperatures climbed too high, but signs of instability are becoming more obvious on all aspects. Driving along the Bridger Range, wet loose slides and smaller wet slabs were widespread by the afternoon.