Bridger Range

Snow returned to the mountains yesterday, with 3-7” falling around Bozeman, Big Sky, and Cooke City, and a trace to 1” near West Yellowstone and Island Park. The primary hazard is avalanches breaking on recently wind-loaded slopes. New snow is hiding visual evidence of this drifting, so seek out slopes generally sheltered from mountain winds where safer conditions exist. Before considering travel in steeper non-wind-loaded terrain, get out a shovel, dig, and test the snowpack for instability related to buried weak layers. Retreat to slopes less than 30 degrees steep if you encounter indicators of instability.

Welcome to the 2025-26 winter forecasting season! It is a special part of our work to share our fascination with mountain travel and avalanches with all of you.

Snow returned yesterday, with 3-7” falling in the mountains around Bozeman, Big Sky, and Cooke City, equal to 0.2-0.6” of snow water equivalent - SWE. Hyalite Canyon came out on top. The storm largely missed the mountains around West Yellowstone and Island Park, where a trace to 1” (0-0.1” SWE) fell in the last 24 hours.

The dividing line between slopes with older snow coverage from storms in October and November is near 8,500 feet. Above this elevation, a combination of crusts and weak layers underlies snow from the last week. Avalanche activity will be generally confined to those slopes that hold a layered snowpack from earlier in the season. 

The primary avalanche problem is wind slab avalanches on recently drifted slopes. Here’s the challenge: winds were strong Monday into Tuesday from the northwest, west, and southwest before calming during yesterday’s storm. New snow will hide visual evidence of wind-drifting and may also hide signs of instability, like cracking. But we know instability exists. On Monday, Mark and I travelled north of Cooke City, finding weak layers typical of an early-season snowpack and agreeing that slopes with recent drifts are the most concerning (observation, video). On Saturday near Fairy Lake, a skier triggered an avalanche and was caught and carried (observation and videos). This weekend in Cooke City, guides reported multiple natural, wind slab avalanches (observation). Seek out slopes generally sheltered from mountain winds and steer clear of upper-elevation terrain near ridgelines and gullies that are often wind-loaded.

Persistent weak layers of sugary facets and surface hoar buried 1-2 feet deep within older snow from October and early November are a secondary concern. Areas where a rider or skier will trigger a persistent slab avalanche are isolated. Yesterday, guides in Cooke City triggered a whumphing collapse near Daisy Pass, a sign that weak layers can fail and potentially slide (observation). Dig and test the snowpack for instability before considering travel in steeper terrain (extended column test video).

Throughout the forecast area, human-triggered avalanches are possible, and the danger is MODERATE on mid- and upper-elevation slopes where snow from the last week of storms sits atop a preexisting snowpack.

Before going out, check over your avalanche rescue and safety equipment (video), and practice an avalanche beacon search to warm up for the season (video).

Please submit your observations on thewebsite to help the community track the evolution of this season’s snowpack.