Island Park

Many avalanches have been triggered and broken naturally in recent days. Expect more of the same today. Continue to avoid riding on or beneath all slopes steeper than 30 degrees. Avalanches will be particularly easily triggered and largest on slopes loaded by recent strong winds, but will be dangerous and large enough to bury you on any steep slope.

Avalanche conditions remain dangerous in many areas.

This is particularly true in the areas near Island Park, West Yellowstone and Cooke City that have gotten more snowfall recently. There have been too many avalanches in recent days to try and list them all (go to the avalanche activity log for a full list). Of particular note is an avalanche yesterday in Targhee Creek in the Lionhead area that broke 3-5 ft deep and almost fully buried a rider, leaving only his hand sticking out of the snow. Slopes that have recently been loaded by very strong south and west winds will be easier to trigger, but the setup for Persistent Slab avalanches is widespread in these regions, even on sheltered slopes (as I saw yesterday in the Lionhead area - video) and at low elevations (Town Hill avalanche). Continuing to avoid riding on or beneath slopes steeper than 30 degrees is the only prudent choice in these areas.  The avalanche danger is CONSIDERABLE at all elevations in the Island Park, West Yellowstone and Cooke City areas. 

In the Northern Madison and Gallatin Ranges, there has been less recent snow, but there are the same weak layers and strong winds have been building slabs above them. Wind Slab avalanches are the primary concern here. They will be deepest, most widespread, and most easily triggered at upper elevations . They will also stabilize more slowly if they have persistent weak layers beneath them (which most slopes do). Avoid steep, windloaded slopes today. Avalanches on sheltered slopes are not at all out of the question, so dig and test the upper snowpack before committing to steep slopes without a wind load. The avalanche danger is CONSIDERABLE at upper elevations in these areas.

The Bridger Range has gotten less snowfall recently, but plenty of wind. Wind slabs will be thickest (up to one or maybe two ft thick) and more dangerous at upper elevations where the avalanche danger is MODERATE (watch Dave’s video from yesterday for a good summary of conditions in the Bridgers).