At least a foot of snow over the last couple days with strong winds creates dangerous avalanche conditions. More snow and wind today will make it easy to trigger wind slab avalanches involving the new snow, and increase the chances to trigger larger avalanches that break 2-3 feet deep on buried weak layers. A safe bet is to avoid riding on and underneath slopes steeper than 30 degrees.
Recent extreme winds added to uncertainty, and any new snow and wind today will further increase the chances of a larger persistent slab.
New snow today will be drifted by strong winds into fresh slabs. These will be easy to trigger, and increase the chance to trigger larger persistent slab avalanches.
Near Cooke City received the most snow over the last couple days which creates dangerous avalanche conditions, especially on wind-loaded slopes where strong winds have blown snow into thicker drifts. Ian was in Cooke City yesterday and saw most slopes were untouched by wind (video). More snow and wind today will make it easy to trigger wind slab avalanches involving the new snow, and increase the chances to trigger larger avalanches that break 2-3 feet deep on buried weak layers (examples of recent Persistent Slab avalanches across the region: Bridger Range, N. Gallatin 1, N. Gallatin 2, N. Madison, Cooke City). A safe bet today is to avoid riding on and underneath slopes steeper than 30 degrees.
Near Bozeman and Big Sky similar conditions will develop through the day, and the size and likelihood of the hazard is dependent on how much new snow falls. Anticipate danger to increase through the day. Plan to avoid steep slopes with fresh drifts of snow, and before riding any steep slope dig down to assess for buried weak layers, or avoid steep slopes altogether. Avalanche danger is CONSIDERABLE in the Bridger, Madison and Gallatin Ranges, and Cooke City.
Island Park and the Lionhead area will get less than a couple inches of snow today, so there is lower danger there, but it remains possible to trigger a large avalanche breaking 1-3 feet deep on buried weak layers. Ian’s video from Tuesday at Lionhead shows the poor snowpack structure that exists. Be especially cautious of steep slopes loaded by recent strong winds. Before riding or crossing any steep slopes, carefully assess the snowpack for buried weak layers and assess the terrain for the consequences if you were to be caught in a slide. Avalanche danger is MODERATE in the Lionhead area near West Yellowstone and Island Park.
