GNFAC Avalanche Forecast for Sun Mar 26, 2023
Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Sunday, March 26th at 7:00 a.m. This information is sponsored by Gallatin County Sheriff Search and Rescue and Spark R&D. This forecast does not apply to operating ski areas.
Since yesterday morning the Bridger Range received 14” of low density snow, Hyalite got 6”, near Big Sky and West Yellowstone got 3-4”, and 1-2” fell near Cooke City. Yesterday wind was out of the northwest at 5-15 mph, and overnight wind shifted to the southeast-southwest. Temperatures are singles to low teens F this morning, and will reach low 20s F today. Wind will be 5-15 mph out of variable directions. Snow showers are expected through today with 4-8” possible near Bozeman and Big Sky, and 2-4” near Cooke City and West Yellowstone.
Dangerous avalanche conditions exist and human-triggered avalanches are likely in the mountains near Bozeman, Big Sky and West Yellowstone. Since Friday night these mountains received 8-20” of new snow equal to 0.6-1.5” snow water equivalent (SWE). New snow amounts have been highly variable, and we received reports of 2-4 feet of low density snow in parts of Hyalite and the Bridger Range. Today a person can trigger large avalanches that involve the new snow. Avalanches will be larger and more likely where more snow fell, especially on slopes that have a hard crust below the new snow or where snow was drifted into thicker slabs. Yesterday, skiers in Beehive Basin saw a natural avalanche that was more than a foot deep and 75’ wide which shows what is possible today (photos). More snow through today will make natural avalanches possible and increase the potential size of human-triggered avalanches.
Additionally, there is a possibility avalanches could break several feet deep on old buried weak layers which would create a massive, likely unsurvivable avalanche (video from Mt. Blackmore). A slide that broke 8-10 ft deep earlier this week on Elephant Mtn. is the latest example of huge avalanches that could be triggered or break naturally today (details and photos). See our avalanche activity list and recent videos for more examples of recent big slides. A good reason to choose objectives that avoid avalanche terrain.
Plan to avoid slopes steeper than 30 degrees altogether, or very carefully assess the stability of new and wind-drifted snow and potential for deep buried weak layers before traveling across or below steep slopes. Conservative decision making and cautious route finding are essential today. Human-triggered large avalanches are likely and avalanche danger is CONSIDERABLE.
In the mountains near Cooke City the main avalanche concern is a person triggering avalanches that break several feet deep on weak layers buried two months ago. On Thursday near Daisy Pass a snowmobiler triggered avalanche broke 4 feet deep, caught two riders, and one of them suffered a broken femur (details and photos, video). Additionally, 3-5” inches of new snow from the last couple days will be drifted into thicker slabs that a person can trigger. If you plan to travel on or below steep slopes, choose smaller slopes that have not been recently wind-loaded and without large consequences such as trees, gullies or cliffs below. Human-triggered avalanches are possible and the avalanche danger is MODERATE.
Please share avalanche, snowpack or weather observations via our website, email (email@example.com), phone (406-587-6984), or Instagram (#gnfacobs).
Dangerous avalanche conditions exist and human-triggered avalanches are likely. Today a person can trigger large avalanches that involve the new snow. Additionally, there is a possibility avalanches could break several feet deep on old buried weak layers which would create a massive, likely unsurvivable avalanche. Conservative decision making and cautious route finding are essential today.
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.
On Wednesday, March 22nd, a snowmobiler was killed in an avalanche in central Idaho. This brings the total number of avalanche fatalities in March to 8 people across the U.S.
More info on each event is available at the Avalanche.org Accidents Page.