Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, January 26 at 7:30 a.m. The Gallatin River Lodge and Lone Peak Brewery sponsor today’s advisory. This advisory does not apply to operating ski areas.
At 4 a.m. temperatures are in the 20s F and winds are blowing 15-25 out the WNW. Today, a cold front descending from Canada will deliver colder air and a chance of mountain snow. Temperatures will drop through the day and most areas should see 1-3 inches of new snow by tomorrow morning. Winds will increase briefly during the frontal passage, but will decrease by this evening. Tomorrow looks to be a cold and dry day.
Gallatin Range Madison Range
Lionhead area near West Yellowstone
The recent pattern of warm and dry weather has made it more difficult to trigger avalanches. Unfortunately, buried weak layers continue to plague the snowpack making human triggered avalanches possible, primarily in steep-rocky terrain where the snowpack is less than a meter deep.
In the mountains near West Yellowstone including the southern Madison Ragne, buried facets exist on all aspects and elevations and the structure of the snowpack is dicey. On Friday, Mark and his partner rode through the entire Lionhead and found numerous avalanches from the past week - many of these were human triggered. These slides happened on all aspects and elevations and ran on facets about a foot off the ground.
The snowpack gets slightly stronger in the mountains near Big Sky. But like a hardened criminal – this area has a long avalanche record and the snowpack should not be trusted.
A secondary concern today will be the development of fresh wind slabs. If today’s storm arrives stronger than forecasted, pockets of wind-blown snow in upper elevation terrain could produce avalanches. Pay attention to changing weather conditions and don’t be afraid to turn around if instability is on the rise.
Today, heightened avalanche conditions exist and human triggered avalanches remain possible. For this reason the avalanche danger is rated MODERATE.
Bridger Range
In the Bridger Range, more slopes are stable than unstable; however, it's still possible to find slopes willing and able to produce avalanches. Likely areas to get into trouble will be in steep-rocky terrain where the snowpack is variable (photo). Terrain around scoured ridgelines and rock outcroppings will be areas to avoid.
Overall, the snowpack in the Bridger Range has gradually gotten stronger but spatial variability means you can still get in trouble. On Friday, I traveled to the west side behind Bridger Bowl and found a surprisingly strong snowpack (video). Also on Friday, another skier on the west side found a slope where the snowpack was weaker and more unstable – a good reminder that what you find on one slope won’t be what you find another.
Now is not the time to let your guard down. Human triggered avalanches remain possible on slopes steeper than 35 degrees which have a MODERATE avalanche danger. Slopes less than 35 degrees have a LOW avalanche danger.
Cooke City
Cooke City continues turn the avalanche screw tighter. Yesterday, a snowmobiler triggered a large slide up Sheep Creek that broke 2-3 feet deep and close to 300 feet wide (photo, photo). The rider triggered the slide near the top of the slope, jumped off his sled and was able to self arrest before being swept away - his sled did not fare so well. The slope was steep, convex and rocky - the ideal location for popping loose an avalanche in these conditions.
Today will be no different. Slopes with a relatively thinner snowpack are ones more likely to slide. Look closely at the avalanche in this photo and notice how the snowpack tapers to bare ground not far above the crown. On more uniform slopes a generally strong and stable snowpack exists.
Today, the avalanche danger is MODERATE on all slopes steeper than 35 degrees and LOW on less steep slopes.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
ANDROID APP
If you have an android phone or tablet, you can download our new free app. It’s a slick way to get the advisory. Search Google Play for GNFAC. An iOS version is coming soon. Stay tuned.
EVENTS/EDUCATION
January 29, 30 & February 1, BOZEMAN : Wednesday and Thursday 7-9:30 p.m.; all day Saturday in field, Advanced Avalanche Workshop with Field Course. Pre-registration is required: https://www.ticketriver.com/event/7114-asmsu-advanced-avlanche-workshop-w-field-course
January 31, February 1, BOZEMAN: Friday 6-8 p.m., Saturday 10-2 p.m; Companion Rescue Clinic. Pre-registration is required: www.rei.com/stores/bozeman.html
February 6, BOZEMAN: Thursday, 6-8 p.m., Beall Park; Women’s Specific Avalanche Awareness Class and Transceiver Practice.
February 8, BUCK RIDGE: Saturday, 10 a.m. to 4 p.m., Companion Rescue Clinic for Snowmobilers, Pre-Registration is required. https://www.ticketriver.com/event/9446
February 8, WEST YELLOWSTONE: Saturday, 7-8 p.m., Holiday Inn, 1-hour Avalanche Awareness lecture.
February 12, BOZEMAN: Wednesday, 6:30-7:30 p.m., MSU Procrastinator Theater, Sidecountry IS Backcountry lecture.
More information our complete calendar of events can be found HERE.