GNFAC Avalanche Forecast for Mon Jan 4, 2021

Not the Current Forecast

Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday, January 4th at 7:15 a.m. This forecast is sponsored by Montana Chevy Dealers and World Boards. This forecast does not apply to operating ski areas.

Mountain Weather

Yesterday the mountains near Big Sky, West Yellowstone and Cooke City got 2-4” of snow and less than an inch fell near Bozeman. Strong southwest wind continued through last night at 15-25 mph with gusts of 30-40 mph. This morning temperatures are high teens to 20s F. Today, temperatures will rise to high 20s to low 30s F with westerly wind at 15-30 mph. Snow is expected this afternoon and tonight. By tomorrow morning 5-8” of new snow is possible near West Yellowstone with 3-6” elsewhere.

Snowpack and Avalanche Discussion

Yesterday in Hyalite, an ice climber was saved by an ice screw placement from being knocked off the wall by a small wind slab triggered by a group above (details here). Luckily, nobody was injured. Strong west-southwest wind over the last 48 hours drifted recent snow into slabs overlying a weak snowpack, and created dangerous avalanche conditions on wind-loaded slopes. Since Thursday the mountains received a series of small storms which totaled 0.5-1.0” of snow water equivalent (SWE). On a typical snowpack this gradual load would cause little concern, but this season’s weak, sugary snowpack can’t be trusted. Our videos from the last two days in Beehive Basin, Taylor Fork and Saddle Peak show the poor snowpack structure that exists in the mountains near Bozeman, Big Sky and West Yellowstone. Our avalanche activity log lists many warning signs of the potential to trigger avalanches on sugary, persistent weak layers.

Today large avalanches can be triggered, and are likely on slopes where strong wind over the last 48 hours concentrated the weight of recent snow into thick slabs. Avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on non-wind loaded slopes. Avoid steep, wind-loaded slopes and anticipate danger to rise if more snow falls this afternoon.

Near Cooke City, avalanches are possible on wind-loaded slopes where moderate to strong westerly winds drifted snow into fresh slabs. On Saturday on Abiathar Peak, skiers triggered a couple wind slabs that could have been harmful, and they luckily avoided being caught (photo and details). Yesterday skiers found fresh slabs that cracked 8-16” deep (details).

Avoid slopes with evidence of recent wind-loading and carefully assess the snowpack before riding steep slopes. The snowpack near Cooke City is deeper and generally lacks widespread buried weak layers. However, a couple avalanches in the last week show that there are a few slopes where buried weak layers exist (photo and details, video). Today avalanche danger is MODERATE on wind-loaded slopes and LOW on non-wind loaded slopes.

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.

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.

  <<    >>