Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Sunday, February 12th at 7:00 a.m. This information is sponsored by Community Food Co-op, Bozeman Splitfest and Gallatin Valley Snowmobile Association. This forecast does not apply to operating ski areas.
This morning there is no new snow and temperatures are teens to mid-20s F. Wind is westerly at 5-15 mph with gusts to 25 mph, and in the Bridger Range wind is 20-30 mph with gusts to 40 mph. Today, skies will be mostly sunny with temperatures reaching mid-30s F. Wind will be west-northwest at 5-15 mph, and possibly stronger in the mountains near Bozeman. The next chance for snow is tomorrow night through Wednesday.
Human-triggered avalanches are possible in the mountains near Cooke City, Bozeman and Big Sky. Early last week these mountains received 8-14” of new snow. Moderate to strong westerly winds drifted the new snow into heavier slabs which added weight to weak layers buried 3-4 feet deep and near the bottom of the snowpack (Hyalite video, Buck Ridge video). Recent drifts have become more stable since they formed 2-3 days ago, but are still a concern where they formed on slopes with buried weak layers. Steep slopes that were wind-loaded over the last week are the most dangerous and should be the first ruled out of your travel plan. If you choose to ride any steep slope, first dig down to look for and test buried weak layers. If you get propagating results in an Extended Column Test, find lower angle slopes.
Warm temperatures and sunshine will cause the snow surface to become wet, and may create a few small loose snow slides or cause cornices to become unstable along ridgelines. Yesterday on Mt. Blackmore in Hyalite skiers had a cornice crack near their feet and break away from the ridgeline (observation). Today avalanches are possible and avalanche danger is MODERATE.
Near West Yellowstone and in the southern Madison and southern Gallatin Ranges avalanches are unlikely. The snowpack has had sufficient time to gain strength since two weeks ago when a large storm caused many natural avalanches (Jan. 31 observation). This trend towards better stability is supported by relatively few avalanches over the last two weeks, buried weak layers becoming less reactive in stability tests, and only a few small storms adding minimal weight (Lionhead video). A small avalanche was triggered by a snowmobiler last Thursday near Tepee Basin (observation), and the last avalanche prior to that was twelve days ago near Lionhead (rider triggered wind slab).
Today, travel on or across steep slopes is generally safe. Most slopes are stable, but as long as there is snow on the ground the chance of an avalanche is never zero. While the odds are in your favor, you can further improve your chances by following safe travel protocols and carefully assessing the snowpack. Before riding or skiing steep slopes dig down 3-4 feet to look for and test buried weak layers (Taylor Fork video). Carry proper avalanche rescue gear and allow no more than one person at a time on steep slopes. The avalanche danger is LOW.
Please share avalanche, snowpack or weather observations 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.
February 16, FREE Avalanche Awareness night for women at REI Bozeman. Time TBD.
February 19, 10 a.m.-2p.m. Companion Rescue Clinic Field Day in the Bozeman area. Required Online Classroom Session at 6 p.m. on Feb 18. Information and course registration are HERE.
March 3-5, Bozeman Splitfest. More info and register here.
Every 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.
Loss in the Outdoors, is a support group for those who have been affected by grief and loss related to outdoor pursuits. Check out the link for more information.
Bruce Jamieson’s videos on Snow Science explain heady topics to the layman. Understanding the avalanche dragon helps keep us alive.