Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday, March 4th at 7:00 a.m. Today’s forecast is sponsored by Highline Partners and Idaho State Snowmobile Association - Avalanche Fund. This forecast does not apply to operating ski areas.
Since yesterday morning no new snow has fallen. Wind has been out of the west-southwest at 5-15 mph with gusts to 25 mph. This morning temperatures are below zero to single digits F, and today they will reach teens to low 20s F. Wind will remain west-southwest at 10-20 mph. Snow showers are possible in the southern part of our forecast area today, with snow throughout the forecast area tonight and tomorrow. By tomorrow morning most areas will receive 1-3” of snow, and near Cooke City 3-5” is possible.
All Regions
Avalanche conditions are dangerous, and large, human-triggered avalanches are likely. We have echoed these phrases for the last two months, and it remains important to stay diligent with conservative terrain choices and careful route finding.
See the Avalanche Log for a comprehensive review of the long list of avalanche activity from the weekend. Many recent avalanches have been the largest of the season, and some are among the largest we have ever seen on those slopes. Yesterday skiers in Hyalite saw an avalanche that broke thousands of feet wide across an entire basin (photos). Near Cooke City, on Saturday riders watched an avalanche on Henderson Mtn which broke 1000’ wide and ran far into the runout covering multiple fresh snowmobile tracks (observation, photo), and yesterday we received photos of big avalanches along the highway 212 snowmobile trail (photos) and near Wolverine Peak (photos).
Ian and I rode in Tepee Basin on Saturday and saw two recent avalanches that broke 1-2 feet deep (video). Yesterday I went to the northern Bridgers and saw a lot of small slabs and loose snow avalanches in the new snow (photo), and saw two slides that were 2-3’ deep and a couple hundred feet wide (photo, photo).
Avalanches were also seen in the northern Gallatin Range (photos, photo), Bacon Rind (photo), Lionhead (photos), and Beehive (photo) over the weekend. Skiers outside the advisory area remotely triggered a slide while ascending a low angle ridgeline above the slope (photos, video), and skiers in Hyalite had many whumphs and long shooting cracks (photos).
Since Thursday 1.5-3 feet of snow equal to 2.1-3.2” of snow water equivalent (SWE) fell, and over the last week 3-5 feet fell, with the highest amounts near Island Park and Cooke City (weather log). Yesterday morning in the Bridger Range a rapid storm deposited 15-20” of snow over 6-7 hours (video). Avalanches can break within or below the recent snow, especially where the wind formed thicker drifts. Additionally, very large avalanches can break on weak snow near the bottom of the snowpack, or on weak layers buried 2-4’ deep below snow from the past week.
With recent snow and multiple widespread buried weak layers making complex snowpack stability, travel advice is to simply avoid slopes steeper than 30 degrees and flatter runout zones below. Now is not a time to outsmart the snowpack and attempt to find stable, steep slopes. Human triggered avalanches are likely and avalanche danger is CONSIDERABLE.
If you venture out, please fill an observation form. It does not need to be technical. Did you see any avalanches? How much snow is on the ground? Was the wind moving snow? Simple observations are incredibly valuable. You can also contact us via 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.
March 8-10: Bozeman Splitfest. Check the Bozeman Splitfest website for event details and avalanche education opportunities offered by the Friends of the Avalanche Center.
Every weekend in Cooke City: Friday at The Antlers at 7 p.m., Free Avalanche Awareness and Current Conditions talk, and Saturday from 10 a.m.-2 p.m. at Round Lake Warming Hut, Free Rescue Practice.
Loss in the Outdoors is a support group for those affected by loss and grief related to outdoor pursuits. Check out the link for more information.
On Friday there were two snowmobilers killed in separate avalanches, in Washington and northern Idaho. Our deepest condolences go out to the families, friends, and all involved.