The Wyoming Department of Transportation has closed Teton Pass this morning for the purpose of conducting avalanche hazard mitigation efforts. Up to two feet of new snow with 2 inches of moisture has fallen in the last 30 hours. This new snow has accumulated on good sliding surfaces and is creating very dangerous avalanche conditions. Large natural avalanches are likely and could run long distances. Travel in avalanche terrain including the run out zones of large avalanche paths is not recommended.
Strong southwest winds have created new wind slabs up to four feet in depth at the higher elevations and up to two feet in depth at the lower elevations. These slabs will continue to increase in volume and depth as the day progresses. Natural avalanche activity and human triggered avalanches are very likely on a variety of aspects at all elevations .
Buried layers of faceted snow exist in the snowpack. Large to very large persistent slab avalanches could fail on these layers with depths from 3 to 5 feet at the higher elevations and 1 to 3 feet at the lower elevations. These dangerous slab could fail naturally or be triggered by the weight of a single person or the release of a surface slab.
After a lull in the snowfall this afternoon and early this evening snow will return to the region. Periods of steady snowfall are expected from midnight until 8 AM and during the early afternoon hours on Tuesday. Snowfall amounts of 6 to 12 inches are possible by tomorrow evening. Temperatures will be in the teens and 20s. Winds will be from the southwest at 10 to 20 with gusts to 25 miles per hour.The recent new snow has accumulated on good sliding surfaces comprised of sun crusts, well-developed surface hoar and areas of wind-packed snow. Today’s rapid loading created unstable conditions on steep slopes. Tomorrow’s general avalanche hazard rating is expected to be high in the Teton Range were up to 30 inches of new snow has fallen in the past 42 hours. The hazard is expected to be considerable in the Togwotee Pass and Greys River areas. Periods of intense snowfall, like the one that occurred this morning, and/or strong winds could rapidly increase the hazard in any of these areas. Conditions are quite dangerous. Serious avalanche accidents are a very real concern.
