GNFAC Avalanche Forecast for Mon Jan 11, 2021

Not the Current Forecast

Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday, January 11th at 7:15 a.m. This forecast is sponsored by Gallatin County Search and Rescue and Stronghold Fabrication. This forecast does not apply to operating ski areas.

Mountain Weather

This morning there is no new snow. Wind is northwest-southwest at 5-15 mph with gusts to 25 mph, and temperatures are teens to low 20s F. Today, wind will be westerly at 10-20 mph, and temperatures will reach high 20s to low 30s F. The next chance for snow is late Tuesday night through Wednesday.

Snowpack and Avalanche Discussion

The mountains have not received new snow the last three days, and westerly wind has been light to moderate. A few days without snow and heavy wind-loading lowers the avalanche danger and likelihood of triggering an avalanche, but conditions are far from safe. It is still possible to trigger big avalanches. Yesterday skiers reported many large collapses in low angle terrain in the southern Madison Range (details, details and photo), and a couple in Hyalite (details). These are signs that on steep slopes it is possible to trigger a large avalanche breaking on weak, sugary snow buried 1-3 feet deep.

Natural and human triggered avalanches over the last week show us the nature of slides that we can trigger today (weather and avalanche log). These photos (photo, photo) of avalanches triggered at Lionhead Ridge on Saturday are good examples. Many recent avalanches were triggered from low angle terrain connected to steep slopes (Cinnamon Creek avy photo, N. Madison avy photo). Some slides propagated wide across terrain features and multiple starting zones (Flanders avy photos and video, Buck Ridge avy video, wide cracks in Bridgers photo). Today, large to very large avalanches are possible to trigger and the avalanche danger is MODERATE. Careful snowpack assessment and cautious route selection are essential to travel on, underneath or adjacent to steep slopes.

In the mountains near Cooke City some slopes have a weak layer of sugary facets buried 1.5-2’ deep. On Friday and Saturday there were multiple human triggered avalanches that broke on this layer, including one on Friday that caught and partially buried three skiers and caused one of them to be evacuated by helicopter due to serious injuries (photos and details). Doug and Dave visited the site on Saturday and made a video describing the slide, and we compiled this accident report. Other recent slides north and west of Cooke City (photo, photo) show us this weak layer of facets is not completely isolated and needs to be kept in mind. Diligently search for this weak layer by digging and performing stability tests. Be cautious of slopes with a relatively shallower snowpack, and wind loaded slopes where weak snow may be buried under a thicker slab. Today, avalanches are possible and avalanche danger is rated MODERATE.

If you get out, please send us your observations no matter how brief. You can submit them via our website, email (, 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.

TONIGHT!, 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.

January 15 and 16, Companion Rescue Clinic, 6-8pm Friday Zoom online, Saturday field session 10am - 2pm. Register 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.

The Last Word

On Friday, a snowboarder died in an avalanche near Park City, Utah. The rider was not carrying any rescue gear. Our thoughts are with those affected by this tragic accident. A preliminary report is here.

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