Tetons

Triggering slabs in very steep terrain remains possible at upper elevations today. The snowpack has gained strength since the last significant snow and wind loading last week. Below 9,000 avalanches are unlikely except in very isolated areas of steep terrain. Though overall snow depths increased last week, coverage remains shallow. Due to the thin coverage, being carried by an avalanche holds the potential for significant injury. Evaluate terrain and the snowpack carefully and consider the consequences prior to committing to a slope.

The National Weather Service has issued a Winter Storm Warning that will be in effect from 11pm tonight until 11pm Friday. Moist southwest flow accompanied with high winds will bring snow to all elevations. Snowfall will begin overnight with 1-3” possible by morning. Snowfall will increase in intensity during the day. By sunset on Thursday expect 10-12” in the Tetons, 6-8” on Togwotee Pass/Continental Divide, and 8-10” in the Grey’s River/Southwest Trails zones. Winds overnight will be out of the southwest in the mid-twenties. Winds speeds will ramp up during the day with averages in the 40-50 mph range in the afternoon. Temperatures will be in the low twenties at 10,000’ with valley locations in the low thirties. The avalanche danger will start out similar to today and rise throughout the day. Rapid loading will help to create unstable conditions. Newly formed wind slabs will be most sensitive later in the day. Initial instabilities will likely involve the new snow and depend on bonding with the wide variety of snow surfaces currently covering the mountains. As loading continues, deeper weak layers within the snowpack will be put under additional stress. By late afternoon, expect the danger to be Considerable in the upper elevations in the Tetons and Southwest Trails and Moderate to Considerable in the upper elevations on Togwotee Pass. At mid and low elevations the danger will likely be Moderate in the afternoon.