GNFAC Avalanche Forecast for Sun Jan 3, 2021

Not the Current Forecast

Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Sunday, January 3rd at 7:00 a.m. This forecast is sponsored by Grizzly Outfitters and Highline Partners. This forecast does not apply to operating ski areas.

Mountain Weather

Since yesterday morning the mountains got 1-3” of new snow. This morning, temperatures are teens to low 20s F and southwest wind is 15-25 mph with gusts of 30-50 mph. Strong southwest-west wind will continue today with gusts over 40-50 mph. Snow showers will favor the southern half of our advisory area this afternoon with more snow expected tomorrow. By tomorrow morning, 5-7” of new snow is possible near West Yellowstone with 3-5” near Cooke City and 1-3” elsewhere.

Snowpack and Avalanche Discussion

Today strong wind creates dangerous avalanche conditions on wind-loaded slopes in the mountains near Bozeman, Big Sky and West Yellowstone. The snowpack has widespread buried layers of weak, sugary facets which have struggled to hold the weight of overlying slabs. Yesterday I saw this unstable snowpack in the Bridger Range near two recent skier triggered avalanches on Saddle Peak (video). These avalanches and reports of large collapses in Hyalite, near Big Sky, West Yellowstone and everywhere in-between (activity log) are warning us that large avalanches are possible to trigger on steep slopes. Strong southwest-west wind will grow fresh drifts and push these weak layers closer to breaking today. Today avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on non-wind loaded slopes. Avoid steep wind-loaded slopes, and carefully assess the snowpack for buried weak layers before riding or crossing any steep slope.

Near Cooke City, today the main concern is where moderate to strong southwest-west winds drifted snow into fresh slabs. Yesterday on Abiathar Peak, adjacent to our advisory area, skiers triggered a couple wind slabs that caught them off guard and they felt lucky to escape (photo and details). Today these slabs will grow thicker and are large enough to be harmful or deadly.

The snowpack near Cooke City is deeper and generally lacks widespread buried weak layers compared to the rest of our advisory area. However, weak snow exists in isolated areas. A skier triggered avalanche yesterday in Yellowstone National Park (immediately outside the advisory area) (photo and details) and a snowmobile triggered avalanche last Wednesday on Crown Butte are examples of these instabilities (video).

Today, freshly drifted snow makes avalanches possible on wind-loaded slopes where avalanche danger is MODERATE. Avalanche danger is LOW on non-wind loaded slopes. Be extra cautious of steep wind loaded slopes, and dig down a few feet to assess the snowpack for buried weak layers.

If you get out, please send us your observations no matter how brief. You can submit them via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).

Upcoming Avalanche Education and Events

See our education calendar for an up to date list of all local classes. Here are a few select upcoming events and opportunities to check out:

Every Saturday in Cooke City, FREE snowpack update and rescue practice at the Round Lake Warming Hut between 10 a.m. and 3 p.m. Poster with More Info.

Tuesday, January 5, 6-7 p.m. The Friends of the Avalanche Center will offer a FREE 1-hr Avalanche Awareness Talk in partnership with The Basecamp and Alpine Orthopedics and Sports Medicine. The talk will be a live, ONLINE event. Join us HERE.  

Monday, January 11, 6-7 p.m. The Friends of the Avalanche Center will offer a FREE 1-hr Avalanche Awareness Talk in partnership with Uphill Pursuits. The talk will be given via a live ZOOM session. Please click the link below to join the webinar: Join HERE.

Tuesday, January 19, 6-7 p.m. The Friends of the Avalanche Center will offer a FREE 1-hr Avalanche Awareness Talk in partnership with the University of Montana Western School of Outreach. The talk will be a live, ONLINE event. Join us HERE

January 20 & 21 (plus field sessions the following weekends), Avalanche Fundamentals with Field Course. There are separate field sessions tailored for both skiers and splitboarders (Bridger Bowl) and snowmobilers (Buck Ridge). Register here.


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