Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Sunday, February 26th at 7:00 a.m. This information is sponsored by Spark R&D and Cooke City Super 8/Bearclaw Bob’s. This forecast does not apply to operating ski areas.
Yesterday morning the mountains near Cooke City and West Yellowstone got 1-2” of snow, and elsewhere got none over the last 24 hours. This morning, temperatures are teens to 20s F, and wind is out of the southwest at 15-35 mph with gusts of 35-80 mph. Today, temperatures will reach high 20s to low 30s F, and wind will be southwest at 15-30 mph with gusts to 40 mph. Snow will begin this morning near West Yellowstone and later elsewhere. By tomorrow morning the mountains could have 3-5” of new snow.
Yesterday near Cooke City, a large natural avalanche buried the Daisy Pass road (photos and details), a skier triggered and was caught in an avalanche near Round Lake (photo), and a large natural avalanche was seen on the east side of Henderson Mountain (photo). Recent strong winds drifted last week’s 4 feet of snow into thick slabs that are easy for a person to trigger, and could avalanche naturally if more weight is added from wind-drifted snow today. Avoid travel across steep wind-loaded slopes and minimize time spent below them. The avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on other slopes.
Early last week the mountains received 2-4 feet of snow (1.5-3.5” of snow water equivalent), and since Wednesday strong wind has drifted that snow into thicker slabs that are possible for a person to trigger. On Friday there were natural and human-triggered slides reported near Big Sky and Hyalite (snowmobile triggered on Buck Ridge, natural on Mt. Blackmore, cornice fall Beehive, natural on Fan Mtn.). Yesterday, in the southern Gallatin Range skiers intentionally triggered a small wind slab (video), and near Hebgen Lake skiers had small wind slabs collapse on low angle slopes (observation).
Overnight wind speeds increased everywhere, except the Bridger Range where speeds decreased slightly. Despite continued strong wind, most of last week’s snow has already been drifted into denser slabs, so slabs are not growing and slopes are getting relief from additional loading. With this break from loading, natural avalanches are unlikely, but recently formed wind slabs can be triggered by a person and still need a day or two to be fully trusted.
Assess the snowpack for signs of recently formed drifts which often appear as round, smooth pillows, and form below cornices, convex rolls and on the opposite side of scoured ridgelines. Travel on slopes that do not have recent drifts or are less than 30 degrees steep. Today the avalanche danger is MODERATE because human-triggered avalanches are possible.
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Heavy snowfall is possible today along with strong winds which will create fresh, unstable slabs. These wind slabs will be easy to trigger and could break naturally. Recently formed wind slabs are also possible to trigger. Identify and avoid wind-loaded slopes.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
March 3, 9 a.m.-3 p.m., Bozeman Splitfest - Companion Rescue Clinic. Classroom session followed by a field session. More information and registration HERE.
March 3-5, Bozeman Splitfest. More info and register here.
March 3 & 4, Companion Rescue Clinic. Online classroom session Friday evening followed by a field session from 10 a.m.-2 p.m. Saturday. More information and registration HERE.
March 9, 6 p.m.-7 p.m., 1-Hour Awareness - Spring conditions. FREE at REI Bozeman.
March 10 & 11, SheJumps - Women’s Companion Rescue Clinic. Online classroom session Friday evening followed by a field session from 10 a.m.-2 p.m. Saturday. More information and registration HERE.
Every Saturday, 10 a.m. - 2:00 p.m. Avalanche Rescue Training, drop in for any amount of time. Round Lake Warming Hut, Cooke City. Free.
Loss in the Outdoors, is a support group for those who have been affected by grief and loss related to outdoor pursuits. Check out the link for more information.
Tragically, On Thursday in Wyoming a snowmobiler was buried and killed in an avalanche. Preliminary details are available HERE.