GNFAC Avalanche Forecast for Tue Mar 25, 2025
This is Dave Zinn with the avalanche forecast on Tuesday, March 25th, at 6:45 a.m., sponsored by the Avalanche Alliance and the Idaho State Snowmobile Association - Avalanche Fund. This forecast does not apply to operating ski areas.
This morning, temperatures are in the high 20s to low 30s F with 10-20 mph winds from the west and northwest. In the last 24 hours, an inch of snow fell in the mountains around Cooke City, with some rain around West Yellowstone and Island Park.
Today, high temperatures will be in the 40s to 50s F with 5-15 mph winds from the west and southwest. Skies will be mostly sunny across much of the forecast area except Cooke City, where overcast skies may produce a few showers.
All Regions
Springtime weather brings several avalanche problems that will evolve throughout the day as temperatures warm well above freezing. Consider what avalanche problem is the most concerning at any given time and where they might overlap, because the management strategy is slightly different for each.
Wind slab avalanches breaking up to a couple feet deep on slopes where winds recently drifted snow are the primary concern. Yesterday, a natural avalanche slid on a wind-loaded slope on the Fin south of Cooke City (details and photo). While instability related to recently wind-drifted snow is decreasing, similar human-triggered avalanches are possible today. Seek out sheltered terrain and avoid heavily wind-loaded slopes immediately below cornices. Note conditions that indicate potential instability, such as a stiffening of the snow surface and shooting cracks.
Wet loose avalanches will slide naturally as the day warms and the snow surface moistens and becomes weaker. These are most likely on southern aspects and slopes with exposed rocks and cliff bands that heat up in the sun. Wet snow avalanches will be relatively small, primarily a hazard in technical terrain where heavy snow could push riders or skiers into obstacles like trees, rocks and off cliffs. Move to shadier, northern aspects if more than the top few inches of snow becomes wet or you observe cinnamon-roll-like pinwheels and small wet snow avalanches in nearby terrain.
Persistent slab avalanches are primarily a concern in the Lionhead, Southern Gallatin and Southern Madison Ranges, and to a lesser extent, the mountains around Cooke City. While not likely, human-triggered avalanches could break 2-3 feet deep and over one hundred feet wide on buried weak layers. This weekend, a natural avalanche broke on this layer in the Sheep Creek drainage (photo), and my partner and I noted the issue in several snowpack assessments over the last two days around Cooke City (photo, video, observation). Saturday and Wednesday of last week, snowmobilers triggered avalanches in the Taylor Fork that broke several feet deep (photos, photos). Reduce your vulnerability by selecting smaller, less consequential slopes with fewer terrain traps and by following safe travel practices. Digging and testing the snowpack increases your chances of catching critical instability before it catches you.
Human-triggered avalanches are possible, and the danger is rated MODERATE across the forecast area.
