Good morning. This is Dave Zinn with the Gallatin National Forest Avalanche Forecast on Sunday, December 1st at 7:00 am. This information is sponsored by Highline Partners and Cooke City Super 8/Bearclaw Bob’s. This forecast does not apply to operating ski areas.
This morning, mountain temperatures are in the teens to 20s F, and the mountains around Bozeman and Cooke City squeezed an inch of snow out of the lingering flurries.
- Mountain winds near Bozeman and Big Sky - 15-20 mph with gusts to 45 mph from the west
- Winds near West Yellowstone, Island Park and Cooke City - 5-15 mph, gusts of 30 mph from the west to the north.
Today's high temperatures will be in the 20s to 30s F under mostly sunny skies, with 5-15 mph winds from the west to the southwest.
All Regions
Today's primary avalanche concern is triggering avalanches on wind-loaded slopes. Steer clear of wind drifts on steep slopes or evaluate the snowpack for instability and underlying weak layers before proceeding.
Wind Slab Avalanches: Winds gusting to 45 mph in the mountains around Bozeman and Big Sky created fresh drifts. Without much recent snow, these slabs will be thin. Yesterday, skiers near Hyalite Peak avoided ridgeline terrain where they observed active wind loading (observation). Older wind drifts are well-bonded other than in areas where they sit on persistent weak layers. Note a stiffening of the snow surface and visual cues of recent drifting when traveling. These will be most likely at higher elevations near ridgelines and around gullies. Cracks shooting from your skis, board, or sled signal the need to avoid steep slopes or redirect to more wind-sheltered terrain.
Persistent slab avalanches: The snowpack is weakening (Cabin Creek, Blackmore videos). Wind slabs will remain unstable for longer where they sit on layers of sugary facets. These weak layers are mainly a concern on higher elevation slopes that had thin snow cover through early November and are now capped with wind-drifted snow. Results from recent avalanche mitigation work at Big Sky Resort demonstrate the risk (photo, photo). Take a few minutes to dig down, look for, and test these weak layers to prevent unpleasant surprises.
Recent avalanche activity: Yesterday, a group in Beehive Basin noted several collapses and unstable test results, indicators of lingering instability (observation). On Friday, skiers on Mt. Blackmore deliberately triggered a minor wind slab avalanche measuring 1 ft deep and 10 ft wide (details and photo). Even a small slide like this can have serious consequences if it pushes you over cliffs or into rocks.
Avalanche danger: Human-triggered avalanches are possible, and the avalanche danger is rated MODERATE across the advisory area.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
TOMORROW, Monday, December 2, 6:30 p.m. MAP community partnership night and Free 1-hr Avalanche Awareness at MAP Brewing
Tuesday, December 10, 9 a.m.-3 p.m., West Yellowstone Avalanche Fundamentals: Motorized Guide Cert Course, Pre-registration required.
For an intro class with a field day, Register for our Avalanche Fundamentals course.
Friends of the Avalanche Center: Fall Fundraiser!
We’re still counting on your support and the online Fall Powder Blast fundraiser is 77% of the way to our goal. Please consider making even a small donation HERE or via Venmo
Bridger Bowl has backcountry conditions and there are no ski patrol services. Please steer clear of snowmaking equipment, chairlifts and snowmobiles, and respect posted signage, while they set up for the season.