Good morning. This is Dave Zinn with the Gallatin National Forest Avalanche Forecast on Thursday, March 23rd at 7:00 a.m. This information is sponsored by the Upper Yellowstone Snowmobile Club, the Gallatin Valley Snowmobile Association and Chad Bunting-Financial Advisor-Edward Jones. This forecast does not apply to operating ski areas.
This morning, mountain temperatures are in the teens F with 5-15 mph wind from the south to northwest, and there is no new snow. Today, clouds will gradually increase, temperatures will be in the upper 20s to low 30s F and the winds will be 10-20 mph from the west to southwest. The mountains will receive a trace to 2” of snow by morning, with a more potent storm arriving tomorrow.
In the southern half of the advisory area, we have two issues. First, smaller avalanches could fail within the 5-9” of snow that fell earlier this week. The resulting avalanche will generally be small, with severe consequences primarily dictated by the complexity of the terrain. Watching for signs of instability and a quick snowpit will provide the needed information to avoid this problem. The second concern fits into a category that we consider “high consequence, low probability” events (video). This is our deep slab avalanche problem.
Stability has greatly improved since last week’s avalanche warning and significant avalanche cycle (Lionhead video, Taylor Fork video). As I discussed in my video above Hebgen Lake yesterday, we remain wary because if you find the wrong spot, and get caught. The result could be unsurvivable. In Cooke City, the fourth rider on a slope triggered a huge avalanche on Henderson Mountain this weekend. Thankfully, he wasn’t caught. If it hadn’t been him, it could have been the tenth or the fiftieth (Cooke City avalanche video).
If you take your chances with low-probability deep slabs, be obsessed with the potential consequences. Rely on your safe travel protocols, choose smaller slopes rather than large ones, and select less wind-loaded terrain (generally, if there is a cornice directly above it, avoid it).
The danger is MODERATE.
On a non-avalanche-related note, I saw the markings from a bear coming out of hibernation in the Lionhead area—time to carry bear spray. I know, if it's not one thing, it's another.
Avalanches are unlikely today in the northern half of the advisory area. Isolated instabilities that you encounter are likely to be small, involving recent snow and surface-level wet snow. The negative consequences of these small avalanches will generally be dictated by the terrain rather than the size of the slide.
Yesterday, skiers at Mount Blackmore noted wet and dry loose snow avalanches (observation). The day before, snowboarders in Big Sky and skiers near Divide Peak noted similar new snow instabilities (observation 1, observation 2) and I saw loose snow avalanches that ran surprisingly far on an ice crust in Frazier Basin (video). Warm temperatures and time have largely improved these instabilities. Use a quick pit to test the upper few feet of the snowpack to uncover isolated instabilities that remain.
The last deep slab avalanches in the north were a little over two weeks ago (Bridger Range details and photos, Hyalite Peak details and photos). This problem is not out-of-mind, but these avalanches are now unlikely.
Follow safe travel protocols every day in avalanche terrain. The danger is rated LOW.
Please share avalanche, snowpack or weather observations via our website, email (firstname.lastname@example.org), phone (406-587-6984), or Instagram (#gnfacobs).
The most likely scenario is triggering relatively small avalanches within the 7-9” of snow that fell earlier this week. Severe consequences will be largely dictated by the complexity of the terrain. The less likely deep slab avalanche problem is more vicious. If you take your chances with low-probability, high-consequence deep slabs, be obsessed with the potential consequences. Rely on your safe travel protocols, choose smaller slopes rather than large ones, and select less wind-loaded terrain. Watch our video from last week on the deep avalanches in Island Park, check out this photo from a snow biker near Jefferson and read this thorough observation of avalanche activity in Hellroaring Creek.
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.
In the last 2 weeks, five people were killed in avalanches. A total of 19 have been killed in avalanches in the U.S. this season. More info on each event is available at Avalanche.org Accidents Page.