Weak layers of faceted snow persist in the snowpack. One is deeply buried and formed in early December. Large slab avalanches have recently been triggered on this layer. Another is comprised of surface hoar that formed in mid-January and has also been responsible for recent avalanche activity. Dense wind slab avalanches and deep persistent slab avalanches could be triggered by backcountry users. Careful terrain and snowpack analysis and a comprehensive understanding of the snowpack structure and implications is warranted. Most avalanche fatalities occur during periods of moderate or considerable hazard. Avalanches are unlikely below an elevation of 7,500 feet.
Dense surface slabs formed by southwest to west winds could be triggered by skiers or riders on steep avalanche prone slopes. These wind slabs could be up to two feet deep.
Dangerous deep slab avalanches continue to be a hazard above an elevation of 7,500 feet. These large slab avalanches could be triggered by the weight of a single person or after a slope has been crossed multiple times by snowmachines. These slabs could propagate long distances, have depths to four feet and could carry severe consequences to anyone involved.
( Discussion is generated from the previous day's afternoon forecast. )A strong and moist westerly flow off of the Pacific will bring periods of snow and blowing snow to the mountains. Snowfall wise this flow will favor the western and northern portions of our forecast region. The higher elevations in those areas are forecast to receive 2 to 5 inches of new snow overnight and several additional inches of new snow during the day. Lesser amounts will fall in the Salt River, Wyoming and Wind River Ranges and at the lower elevations. Cooler air will move into the region. Temperatures will be in the teens in the mountains and in the 20s at the lower elevations. Winds will be westerly at 30 to 45 with gusts to 70 overnight and decrease to 20 with gusts to 30 miles per hour by tomorrow evening.At the mid and upper elevations (7,500 to 10,500 feet) backcountry users could trigger wind slab avalanches 1 to 3 feet in depth and large deep persistent slab avalanches up to four feet in depth. The general avalanche hazard is expected to be MODERATE at those elevations and LOW below an elevation of 7,500 feet.
