GNFAC Avalanche Forecast for Mon Jan 6, 2020

Not the Current Forecast

Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday January 6th at 7:00 a.m. Today’s forecast is sponsored by Uphill Pursuits and Gallatin County Search and Rescue. This forecast does not apply to operating ski areas.

Mountain Weather

Yesterday the mountains got 1-2” of new snow. Overnight west-southwest wind increased to 25-40 mph with gusts of 40-55 mph. This morning temperatures are single digits to mid-teens F. Today temperatures will be teens to low 20s F with west wind at 25-50 mph. Snow today and tonight will favor the mountains near Cooke City with 8-10” possible by morning. The mountains near West Yellowstone will get 3-5”, and near Bozeman and Big Sky will get 1-2”.

Snowpack and Avalanche Discussion

Today strong wind and new snow will increase the avalanche danger. New snow will be drifted into fresh slabs that are possible to trigger. The weight of these fresh drifts may break avalanches deeper in the snowpack, similar to those triggered by snowmobilers last weekend (photos). Over the weekend skiers near Cooke City observed cracking, settling and unstable test scores below the new snow that fell since Wednesday (details, snowpit). Last Thursday Ian found weak layers below the 1-2 feet of new snow, and he warned to give them time to stabilize (video). Natural avalanches are possible, especially on slopes where thick drifts grow through the day. Avoid steep slopes and be extra cautious below slopes being rapidly loaded by wind-drifted snow. Avalanche danger is CONSIDERABLE.

Saturday, on Buck Ridge near Big Sky a snowmobiler triggered a very large avalanche that partially buried two other riders (details). Yesterday Doug and I visited the slide and were wide eyed when we approached the 10 foot deep crown (photo, photo, video). Dave was at Beehive Basin where he witnessed a dog break a massive cornice that sent a large avalanche down the slope below (video, photo). The dog was okay. Today similar avalanches are possible to trigger, but do not expect similar lucky outcomes.

Weak layers buried deep in the snowpack were overloaded by snow and strong wind last week, and large avalanches were triggered and broke naturally. See our photos page and avalanche activity log for a comprehensive view of types of slides that are possible to trigger today. Avoid heavily wind loaded slopes, identifiable by large overhanging cornices or big round pillows of snow, stay far back from the edge of cornices (tell your dog), and avoid steep slopes where you suspect buried persistent weak layers.

Strong wind will continue today and drift snow into fresh slabs. Danger will increase through the day. Natural avalanches are possible on wind loaded slopes and human triggered avalanches are possible on all steep slopes. Avalanche danger is CONSIDERABLE on wind loaded slopes and MODERATE on other steep slopes.

If you get out, please send us your observations no matter how brief. You can fill out an observation form, email us (, leave a VM at 406-587-6984, or Instagram (#gnfacobs).

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out and plan to attend one or two: Events and Education Calendar.


Every Friday and Saturday, Snowpack Update and Rescue Training. Friday, 6:30-7:30 p.m. at the Soda Butte Lodge. Saturday anytime between 10-2 @ Round Lake.


January 25, 1-hr Avalanche Awareness, 7-8 p.m. at West Yellowstone Holiday Inn.


January 7, Women's Specific Avalanche Awareness + Beacons, 6-8 p.m. at Story Mill.

January 8, 1-hr Avalanche Awareness, 6-7 p.m. at REI.

January 8, 1-hr Avalanche Awareness, Gallatin Valley Snowmobile Association Groomer Building.

January 10 & 11, Companion Rescue Clinic, 6-8 p.m. on the 10th at REI and 10-2 p.m. on the 11th at History Rock. More info and Register Here.

January 15 and 16, Introduction to Avalanche w/ Field Course, evenings of January 15 & 16 plus one field day either January 18, 19 or 25. Snowmobile specific field day offered January 25. More info and Register Here.

The Last Word

On New Year’s Day, two snowmobilers lost their lives in an avalanche near Seeley Lake, northeast of Missoula. Our condolences go out to their friends and families. The West Central Montana Avalanche Center has released a preliminary report.

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