Up to a foot of new snow with an inch of moisture has fallen in the last 30 hours. This new snow has accumulated on good sliding surfaces and is creating dangerous avalanche conditions. Additional snowfall will continue to increase the avalanche hazard during the day. Human triggered avalanches are likely. Large natural avalanches are possible and could run long distances. Expert terrain assessment and route finding skills are essential for safe travel in avalanche terrain.
Southwest to west winds have created new wind slabs up to two in depth at the higher elevations and a foot in depth at the lower elevations. These slabs will continue to increase in volume and depth as the day progresses. Natural avalanche activity is possible and human triggered avalanches are likely on a variety of aspects at all elevations.
Buried layers of faceted snow exist in the snowpack. Large persistent slab avalanches could fail on these layers with depths from 2 to 4 feet at the higher elevations and 2 feet at the lower elevations. These dangerous slab could fail naturally or be triggered by the weight of a single person or the release of a surface slab.
( Discussion is generated from the previous day's afternoon forecast. )The next disturbance will approach later this evening and bring another round of moderate snow. The steadiest snowfall is forecast to fall from late tonight into tomorrow morning with lighter snow after that. Six to ten inches of new snow are possible by tomorrow evening. Temperatures will be cooler. They will be in the 20s. Southwest winds will decrease to 20 with gusts to 30 miles per hour.Winds slabs will continue to form on leeward aspects and lie upon good sliding surfaces. Slab depths are likely to increase to 1 to 2 feet in areas with lesser new snow totals and 2 to 3 feet in areas most favored by the recent snowfall. These slabs are likely to be easily triggered by humans. Natural releases are possible. The new snow and winds are also increasing the load on persistent weak layers that are more deeply buried in the snowpack and in areas where the snowpack is shallower and has poor structure. Persistent slab avalanches 2 to 4 feet in depth could fail on weak layers of faceted snow due to the weight of a person or due to the release of a surface slab. The general avalanche hazard is expected to be considerable in areas that have received the most new snow since the start of this storm cycle on Saturday night. Those areas include the mid and upper elevations of the Teton forecast zone. The general avalanche hazard in the Greys River, Togwotee Pass area and the lower elevations of the Teton zone are expected to be moderate.
