GNFAC Avalanche Forecast for Mon Mar 20, 2023

Not the Current Forecast

Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday, March 20th at 7:00 a.m. This information is sponsored by Stronghold Fabrication, Knoff Group Real Estate and Cooke City Motorsports. This forecast does not apply to operating ski areas.

Mountain Weather

This morning there is 1” of new snow near West Yellowstone and none elsewhere. Temperatures are teens to low 20s F. Wind is out of the south-southwest at 5-20 mph with gusts of 25-35 mph, and in the Bridger Range wind is out of the southeast-east. Today, temperatures will reach high 20s to low 30s F, and wind will be out of the southwest-southeast at 5-25 mph. Snowfall is expected through today with 3-4” possible by this evening and another 2-4” overnight.

Snowpack and Avalanche Discussion

The primary avalanche concern is the possibility for a person to trigger an avalanche that breaks on persistent weak layers buried at least 2-6 feet deep below hard slabs of snow. On Saturday near Cooke City a snowmobiler triggered a huge deep slab avalanche and was luckily unharmed (details and photos). Yesterday, Dave and I rode in Taylor Fork and saw multiple deep slab avalanches that broke during heavy snowfall last week (video, observation and photos). These avalanches broke on weak layers that were formed and buried in January. Over the past month, we have seen these large to very large avalanches break each time the mountains receive new snow (weather and avalanche log), a sign we will be dealing with this instability as long as it keeps snowing. 

We have seen the majority of deep slab avalanche activity near Cooke City and West Yellowstone (Lionhead observation, video), where more snow fell over the last month, but the possibility to trigger a large, deep avalanche also exists near Bozeman and Big Sky (Hyalite Peak slide, Northern Bridgers slide). Before traveling on or underneath any steep slope, evaluate the snowpack for buried weak layers and wind-loading. Ski or ride small, simple slopes with minimal wind-loading, or slopes less than 30 degrees.

New snow today will be drifted into fresh slabs that could avalanche under the weight of a person, and add weight to the snowpack to increase the chances of triggering a deeper avalanche. Watch for cracking across the snow surface around your feet or skis as a sign fresh drifts are unstable and could avalanche on steeper slopes. Today’s snowfall will not rapidly increase the danger, but conditions will be dynamic. Choose objectives that are mellow, low consequence or low angle, or be ready to adjust your plan if you notice heavy snowfall or drifts growing quickly. 

Heightened avalanche conditions exist and avalanche danger is MODERATE.

Please share avalanche, snowpack or weather observations via our website, email (, phone (406-587-6984), or Instagram (#gnfacobs).

In Island Park, heavy snowfall today will create dangerous avalanche conditions on wind-loaded slopes. Fresh drifts will be easy to trigger and their additional weight could cause avalanches to break deeper in the snowpack. Cautious route finding and conservative decision making are essential. See Doug’s video for a rundown on the aftermath of last week’s avalanche warning.

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.

Sunday, March 26, Avalanche Alliance Sweepstakes! Win a custom 2022 Ford 350 Super-Duty truck or many other items. Proceeds help support avalanche centers. Use code LASTCHANCE to receive 40% more tickets. Winners will be chosen at the Jackson Hole Hill Climb. 

Loss in the Outdoors is a support group for those affected by grief and loss related to outdoor pursuits. Check out the link for more information.

The Last Word

Over the last ten days, five people were killed in avalanches in the U.S. A total of 19 people have been killed in avalanches in the U.S. this season. More info on each event is available at Accidents Page.

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