Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast issued on Sunday, March 10th at 7:00 a.m. Today's forecast is sponsored by Highline Partners and the Yellowstone Club Community Foundation. This advisory does not apply to operating ski areas.
Yesterday the mountains received 2-3” of snow near West Yellowstone and Cooke City, and a trace to 1” elsewhere. Wind has been west-southwest at 5-15 mph with gusts to 25 mph. This morning temperatures are single digits F. Today temperatures will reach low 20s F under mostly sunny skies, and wind will be out of the west-southwest at 10-20 mph. The next chance for snow is late Tuesday.
All Regions
Since Tuesday steady light snow buried a weak layer of facets 8-16” deep. This weak layer does not exist on all slopes, but recent avalanches are evidence some slopes are unstable. Yesterday on Buck Ridge snowmobilers experienced a collapse and got unstable test results below the recent snow (details). On Friday near Cooke City Doug saw natural and human triggered slides that broke below the recent snow (details). On Wednesday a skier triggered an avalanche on Mt. Blackmore (photo), and on Friday skiers in Hyalite saw recent avalanches and had unstable test results on this weak layer (details). Eric and I did not find this layer in the Bridger Range or Cabin Creek in the southern Madison Range (video), and yesterday we did not find it in all three pits we dug in Hyalite (video). Before riding steep slopes dig a couple quick pits to test the new snow/old snow interface. If it breaks stick to lower angle terrain.
Moderate southwest wind formed fresh drifts that can avalanche under the weight of a skier or rider. These wind slabs are easier to trigger where they formed over weak facets. Avoid steep wind loaded slopes, especially if you see cracking of the snow surface in lower angle terrain.
Sunshine today will be the most intense so far this winter. Wet loose avalanches are possible on steep sunny slopes. These can be deadly if they catch you above cliffs, rocks or other terrain traps. These slides can also trigger a larger slab avalanche (photo). Be cautious of travel below steep, rocky slopes that receive direct sun where wet slides can release naturally.
Avalanches breaking on weak facets near the base of the snowpack are unlikely, but have large consequences. Skiers north of Big Sky yesterday reported crowns of old slides that broke on weak snow deep in the snowpack (photos). Avoid heavily wind loaded terrain, and complex rocky terrain with variable or shallow snow depth (3-5 feet) (video).
Today avalanches are possible and avalanche danger is rated MODERATE.
Use the Regional Pages under the Forecast tab to get a more detailed look at activity, snowpack and weather in the area you plan to visit.
If you get out and have any avalanche or snowpack observations to share, contact us via our website, email (mtavalanche@gmail.com), phone (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: Events and Education Calendar.
The accident report for the avalanche fatality in the Bridger Range on February 26th is complete. You can view the report here.