The snowpack continues to adjust to the very large loading that occurred during the first two weeks of January. Today's strong winds and new snow will be forming pockets of new shallow wind slab and adding more weight to persistent weak layers that are deeply buried in the snowpack. Many very large slab avalanches released naturally on Tuesday in response to an extended storm cycle. At the mid and upper elevations skiers and riders could still trigger large destructive avalanches on those problem layers. At all elevations smaller wind slab avalanches could be human triggered in steep wind loaded avalanche starting zones. A careful evaluation of the snowpack and conservative terrain choices are warranted.
Strong winds will be forming shallow pockets of new wind slab on leeward aspects. These fresh slabs could be up to a foot deep and are likely to be sensitive to human triggers during today's frontal passage.
Dangerous deep slab avalanches could be human triggered on a variety of aspects. These persistent slab avalanches could step down to depths of 4 to 8 feet at the mid and upper elevations and to depths of 1 to 3 feet below an elevation of 7,500 feet. Although these destructive slab avalanches are more likely to be triggered by snowmachines the weight of a single skier could also trigger a very large deep slab avalanche.
( Discussion is generated from the previous day's afternoon forecast. )The last in a series of storms will move through the Great Basin and into Western Wyoming. Areas of light snowfall will develop overnight and become widespread in the predawn hours. This system is fast moving with strong winds. It should bring 4 to 8 inches of snow to the mountains by Friday evening. Winds may gust from 50 to 60 miles per hour on the peaks. Temperatures will be in the teens in the mountains and in the 20’s at the lower elevations.Strong winds and new snow will form new wind slabs on leeward aspects. These small slabs may grow to depths of 8 to 16 inches and are likely to be sensitive to skiers and riders during this storm period. The blowing snow will also increase the load on persistent weak layers that have recently produced very large slab avalanches. The general avalanche hazard is expected to be considerable at the upper elevations and moderate or low (in the Togwotee Pass area) below an elevation of 7,500 feet.
