Rapidly accumulating new snow and strong westerly winds are forming new wind slabs on steep leeward terrain features. In addition to this new snow problem, this added load will further stress recently buried weak layers that have been very active over the last 5 days. The size and sensitivity of both of these avalanche problem types will increase as they are further loaded today. Dangerous avalanche conditions exist, particularly at higher elevations where avalanches can be large to very large. Evaluate the snowpack carefully to identify layers of concern and simply make conservative decisions to avoid steep avalanche paths.
Strong winds are forming new soft slabs in leeward terrain. These slabs will be small in the morning but could increase to having depths of 18 inches later in the day.
Weak faceted snow that was buried by recent storms can be found at all elevations and on all aspects. Many avalanches have been remotely triggered or directly triggered by backcountry users over the last several days. Weight from this new snow will increase stresses on these weaknesses, making them more sensitive as the day progresses. Above 8000 feet, slabs failing on this layer could have depths of two to four feet while slab depths to two feet are possible at lower elevations.
After the brief lull in the weather this evening, cloud cover is expected to increase overnight. Skies will be partly cloudy in the morning and then overcast by the late afternoon. Periods of light snowfall are expected over the forecast area with an accumulation of an inch or less and steady snowfall is expected to develop tomorrow night. Winds will be westerly to northwesterly at fifteen to thirty miles per hour. Temperatures will drop into the single digits and then tomorrow warm into the teens in the mountains and twenties in the valleys. Today's storm has formed wind slabs above 8,500 feet and also added weight to persistent weak layers at all elevations. These weak layers are buried one to four feet within the snowpack. Careful snowpack assessment and terrain selection are essential for skiers and riders to avoid triggering an avalanche. In the Tetons, the avalanche hazard is expected to remain Considerable at the upper elevations. This week there have been many human-triggered slides, and just a few days ago, snowmobilers remotely triggered a large avalanche. Keep in mind the potential weak structure that may be found on some slopes. In the Togwotee Pass and Grey’s River forecast areas, the avalanche hazard is expected to remain Moderate. Backcountry travelers could trigger large avalanches one to four feet in depth. Yesterday, a skier remotely triggered a large avalanche near Palisade Lake, and today, snowmobilers triggered multiple large avalanches 2 feet in depth with wide crowns by Sheep Creek Pass in the Snake River Range. This is a reminder of the poor structure that exists in the forecast area.
