Island Park

New snow and wind are adding weight to a snowpack with weak layers near the ground, increasing the chances for a person to trigger a big persistent slab avalanche today. The new snow and wind alone are enough to create fresh wind slabs that can easily be triggered and may be large enough to bury or injure a person. Choose routes that avoid slopes steeper than 30 degrees, and be cautious of flatter terrain directly below steep slopes.

Avalanche conditions vary widely across our forecast area. In the southern half, new snow, wind, and a snowpack with buried weak layers create dangerous avalanche conditions. The mountains closer to Bozeman and Big Sky have received less snowfall since the start of 2026, and avalanches breaking on weak layers near the bottom of the snowpack are less likely.

Dangerous avalanche conditions exist near Island Park, West Yellowstone, and in the Southern Madison and Southern Gallatin ranges, and the avalanche danger is CONSIDERABLE. Buried weak layers produced big avalanches over the last couple weeks (video, observations from Lionhead on Friday; video, observation from Taylor Fork on Saturday). Today’s new snow and wind are adding weight to the snowpack, increasing the chances for a person to trigger a big persistent slab avalanche. The new snow alone can be a hazard and produce large avalanches, especially where it is drifted into thicker slabs. On non-wind loaded slopes, storm slab avalanches are a possibility in areas with 8-12”, or more, of heavy new snow. Slopes steeper than 30 degrees should be avoided, and be cautious of flat terrain below steep slopes.

Near Cooke City, the main hazard is wind slab avalanches where up to a foot of new snow from the last couple days and today is drifted into thicker, stiffer slabs. Buried weak layers also exist near the bottom of the snowpack, and heavy, steady snowfall in December caused many large avalanches. Now those weak layers are buried very deep on most slopes and persistent slab avalanches are difficult for a person to trigger, but could be massive if you hit a shallower, weak spot on the wrong slope (last Monday’s avalanche on Chimney Rock is an example). Be cautious of big, steep slopes with shallower snowpacks or more variable snow depths due to factors like wind-loading. Avoid freshly wind-loaded slopes, especially if you see signs of instability like cracking across the snow surface or natural avalanches. Near Cooke City avalanche danger is CONSIDERABLE at upper elevations and MODERATE otherwise.

The mountains closer to Bozeman and Big Sky have received less snowfall since the start of 2026, and avalanches breaking on weak layers near the bottom of the snowpack are less likely, though still possible in a few areas. A few inches of snow earlier in the weekend was drifted into wind slabs (Mt. Blackmore wind slabs, north Bridgers). These wind slabs have mostly stabilized and are unlikely to be triggered today, but are worth keeping an eye out for, especially in terrain where a slide could have big consequences, like above cliffs, trees or gullies. 

Avalanche danger is MODERATE in the Northern Gallatin and Northern Madison ranges. Stay cautious of big open slopes where a persistent slab could be triggered from a shallower spot and break deep and wide. In the Bridger Range avalanches are unlikely, generally safe avalanche conditions exist, and the avalanche danger is LOW.