Conditions are dangerous and are likely to be that way for a while. Steep slopes are unstable and have produced large slab avalanches. A snowboarder died yesterday after he was fully buried at the base of a steep creek bank. A snowmobiler died in the Salt River Range on Wednesday after his group was caught in an avalanche and he was fully buried. This area has received five feet of new snow in the past 3 weeks. This snow lies upon persistent weak layers of faceted snow. Large slab avalanches involving all this new snow can be easily triggered by snowmobiles and skiers on steep slopes. Natural avalanche activity is possible. The general avalanche hazard is considerable today above an elevation of 8,000 feet and moderate below that elevation. Expert terrain and route selection skills are essential for safe travel in avalanche terrain.
At the higher elevation, humans could trigger large to very large slab avalanches on persistent weak layers of faceted snow. These dangerous avalanches could be three to six feet deep and could run long distances. At the lower elevations, below an elevation of 8,000 feet, small to large slab avalanches 1 to 3 feet in depth could be human triggered on steep avalanche prone slopes.
In steep, wind-loaded terrain above 8,000 feet, skiers and riders could trigger small to large wind slabs 1 to 3 feet deep. These wind slabs could step down to weak layers deeper in the snowpack and become a large persistent slab avalanche.
( Discussion is generated from the previous day's afternoon forecast. )Conditions will be mostly dry except for some isolated snow showers until midnight. The next storm system is fast moving and will bring snow that could become heavy at times between 2 am and noon. After a lull in the precipitation a second wave of moisture, which is slower moving, will arrive in the evening. Winds will back to the southwest, increase to 25 miles per hour with higher gusts and bring warmer air into the region. Tomorrow's temperatures are expected to rise into the 20s.In the Greys River and Togwotee Pass areas conditions are dangerous and are likely to remain that way. Recent new snow lies upon older faceted persistent weak layers and is unstable on steep slopes. Slab avalanches can be easily triggered by the weight of a person. The new snow is deep and therefore this situation can produce large, dangerous slab avalanches that could be three to six feet deep. In these areas the general avalanche hazard is expected to be considerable. In the Teton forecast area visibility has been limited. Several very large slab avalanches are known to have occurred in response to recent snowfall and wind events. With more snow and wind in the forecast conditions are expected to remain dangerous at the upper elevations where the general avalanche hazard is expected to be considerable. A moderate hazard is anticipated at the mid and lower elevations. Large to very large slab avalanches are possible and could be 2 to 5 feet deep.
