Good morning. This is Ian Hoyer with the Gallatin National Forest Avalanche Forecast on Friday, March 17th at 6:45 a.m. This information is sponsored by Avalanche Alliance and Grizzly Outfitters. This forecast does not apply to operating ski areas.
There is no new snow this morning. Winds are light out of the north and west. Temperatures are in the single digits and teens F. Under sunny skies, temperatures will rise into the 20s and low 30s F. Light winds will continue, shifting more southerly this afternoon. Mild, mostly sunny weather continues through the weekend.
Don’t be tricked by today’s beautiful weather. Avalanche conditions remain dangerous in the mountains around West Yellowstone and Cooke City. Two days of sunny skies does almost nothing to stabilize the deeply buried weak layers. The weak layers deep in the snowpack are still straining under the weight of the 2 to 3 feet of snow (2-2.5” snow water equivalent) that fell mid-week (Tepee Basin video). Human triggered avalanches are likely. Avalanches could break beneath the new snow and be plenty deep to bury you or break on the weak layers deep in the snowpack and be huge and likely unsurvivable. Avoid riding steep slopes and also give them a wide berth when crossing beneath them so you don’t get buried from above.
In addition, warm temperatures and strong spring sun add a whole other set of concerns. Cornices are primed to break off. Stay way back from the edge while traveling on ridgelines and before traveling beneath them remember that a huge cornice falling onto a slope is a perfect trigger for a big deep slab avalanche. Sunny slopes could see the snow surface getting wet this afternoon. With so much new snow loose wet avalanches could be large enough to be quite dangerous.
Roof avalanches are also a real concern as roofs shed their winter snowpack. There was a close call earlier this week in Island Park, ID with an 8 year old girl completely buried for half an hour before being found and dug out. Keep kids well away from snowy roofs when they’re playing outside and be wary about shoveling a roof out while solo.
The avalanche danger is rated CONSIDERABLE.
The mountains around Bozeman and Big Sky got half as much snow in this last storm (around a foot), so large avalanches are a bit less likely, but still possible. There are weak layers throughout the snowpack that are still adjusting the storm’s load and while the new snow has started to bond, you could still trigger a slide breaking there as well. A smaller avalanche in the new snow could then trigger a deeper, larger slide. Loose wet avalanches will be thinner, but could push you off a cliff or into trees. Before riding steep slopes carefully assess the upper snowpack and keep the possibility of deeper slides in mind.
Human triggered avalanches are possible and the avalanche danger is MODERATE.
Please share avalanche, snowpack or weather observations via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
Don’t be tricked by today’s beautiful weather. Avalanche conditions remain dangerous. Avalanches could break beneath the new snow and be plenty deep to bury you or break on the weak layers deep in the snowpack and be huge and likely unsurvivable. Avoid riding steep slopes and also give them a wide berth when crossing beneath them so you don’t get buried from above. See Doug’s video from yesterday on Sawtelle Peak for a rundown on the aftermath of this 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.
Saturday, 10 a.m. - 2:00 p.m. Avalanche Rescue Training, drop in for any amount of time. Round Lake Warming Hut, Cooke City. Free.
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.
A list of all avalanche activity from our forecast area is available HERE.