Dangerous avalanche conditions exist. Recent snow and yesterday's strong southwesterly to northwesterly winds have added load to a snowpack that has buried weak layers. Avalanches could occur in the form of wind slabs at the higher elevations or as persistent slabs at all elevations. Although natural avalanches have become unlikely, human triggered avalanches are likely today and could be triggered remotely. Cautious route finding and conservative decision making is essential for safe backcountry travel.
Recent snow could be triggered as wind slabs in steep terrain above 8500 feet. These sensitive soft slabs were formed during strong southwest to northwest winds and could have depths to two feet. These slabs may become more sensitive this afternoon as they are weakened by rapidly warming temperatures and direct sunlight.
Persistent weak layers of faceted snow exist throughout the backcountry. Above 9000 feet these weaknesses are less prevalent and less sensitive but, if initiated, the result could be very large hard slabs with depths of three to five feet. They will be more sensitive at the mid elevations where they could be hard or soft and have depths of two to four feet. At the low elevations the structure of the snowpack is very poor. At these elevations, slabs will be sensitive and are likely to involve faceted snow to the ground with depths to two feet. The sensitivity of these slabs will also increase as temperatures warm and the snowpack adjusts to the recent load.
A transitory ridge of high pressure will exit the region tonight, and a weather disturbance will increase cloud cover with light snowfall expected by the morning. Accumulation amounts are expected to be one to three inches. Mountain temperatures will start in the mid-teens and then warm into the upper teens to twenties. Ridgetop winds at 10 to 20 miles per hour will veer to the west. Dangerous avalanche conditions, involving snow from a recent storm as well as deeper weak layers, exist across the forecast region. Skiers and riders could trigger small to large wind slab avalanches above 8,500 feet and persistent slab avalanches with slab depths three to five feet at the upper elevations. In the Teton and Grey’s River forecast areas, the avalanche hazard above 7,500 feet is expected to be Considerable, and on Togwotee Pass above 8,000 feet, the avalanche hazard is expected to be Moderate.
