Heavy snowfall, strong winds and warming temperatures have combined with a poor snowpack structure to create very dangerous avalanche conditions. Travel in avalanche terrain is not recommended. Large to very large natural avalanche activity is likely on a variety of aspects at all elevations. Human triggered avalanches are very likely.
Dense wind slabs have formed on a variety of aspects at all elevations. These slabs will increase in depth and volume as the day progresses. Crown depths of one to three feet are expected. These slabs are likely release naturally and to be easily triggered by humans who venture into steep terrain. Once triggered these slabs could step down to buried weak layers.
Large to very large persistent slabs with depths of three to five feet are likely to release naturally or be triggered by humans or the release of surface slabs. The likelihood of triggering these slabs will increase during the day as a snowpack with poor structure continues to be rapidly loaded by strong winds and new snow.
( Discussion is generated from the previous day's afternoon forecast. )The second wave of this storm is expected to arrive during the early morning hours and peak during the day. This pulse will be accompanied by very strong west winds at speeds of 25 to 40 with gusts over 60 miles per hour at the pass and summit levels that will create areas of blowing and drifting snow. New snow accumulations of 4 to 8 inches are expected in the mountains overnight and will continue to favor the Salt River Range, the Snake River Range and the southeast highlands of Eastern Idaho with the lesser amounts likely on Togwotee Pass. Another 6 to 8 inches of accumulation are likely during the day before a possible decrease in these snowfall rates on Saturday night. Temperatures will rise into the 20s in the mountains during the day and into the 30s in the lowest elevations where a mix of snow and rain is possible in the afternoon.The general avalanche hazard is expected to increase to HIGH in the Southwest Trails/Greys River and at the upper elevations of the Tetons, areas which are expected to continue to receive the most snowfall. Travel in avalanche terrain is not recommended in those areas. The general avalanche hazard in the Togwotee Pass/Continental Divide area is expected to increase but remain CONSIDERABLE. Expect knowledge and conservative terrain choices will be necessary for safe travel in avalanche terrain where the hazard is considerable. In all areas the hazard will be increasing. The new snow, warming temperatures and strong winds will create dangerous avalanche conditions. Natural avalanche activity is likely or possible and large human triggered avalanches are likely. Poor snowpack structure presents the likelihood for surface slab avalanches to step down to deeper weak layers with total depths of three to five feet.
