Rapid loading is beginning and dangerous avalanche conditions will develop. The National Weather Service has issued a Winter Storm Warning through 11 PM tonight, and temperatures are starting out 10 to 15 degrees warmer than yesterday morning. As the day progresses, the chance for backcountry travelers to trigger newly developed wind slabs will be on the rise above 7,500 feet. Up there, the likelihood of triggering large persistent slab avalanches will also increase throughout the day. These deeper slabs could step down from the release of a wind slab. Natural activity will become possible. Conservative terrain choices will be essential for safe travel in the backcountry. Below 7,500 feet, the possibility of triggering shallow pockets of soft slab could develop.
New snowfall, ample snow available for transport and strong southwesterly ridgetop winds have combined to build wind slabs in leeward terrain. These slabs are forming on dry settled powder, surface hoar and sun crusts. Skiers and riders venturing into steep, wind loaded terrain could easily trigger these slabs with depths up to 18 inches by this evening.
Layers of weak, faceted snow exist in the snowpack. The chance for backcountry travelers to trigger persistent slab avalanches will be on the rise as load is added onto these weak layers. By the end of the day, these slabs could reach depths of two to four feet.
( Discussion is generated from the previous day's afternoon forecast. )The National Weather Service has issued a Winter Storm Warning beginning at midnight and continuing through 6 PM on Sunday. A quick moving, potent winter storm will bring moderate to heavy snowfall to the region overnight and through midday on Sunday before snowfall intensity begins to decrease in the afternoon. Southwesterly to westerly ridgetop winds will increase to 25 to 35 miles per hour with gust to near 50. Mountain temperatures will rise into the upper teens during the day.Dangerous avalanche conditions are expected on Sunday, and the general avalanche hazard will rise to Considerable. Rapid loading will continue to build new wind slabs and load existing weak layers of faceted snow that reside deeper in the snowpack. Skiers and riders that venture into steep terrain will be likely to trigger these newly developed slabs, and the chance of triggering persistent slab avalanches will also be on the rise. These persistent slabs, which could range in depth from two to four feet, could also step down from the release of a smaller wind slab. Natural avalanche activity will also be possible. Conservative terrain choices will be essential for safe travel in the backcountry on Sunday.
