Heavy recent snowfall particularly on the west slopes of the Tetons combined with moderate westerly winds have created easily triggered soft slabs to two feet or more in depth on avalanche prone slopes at mid and upper elevations. At low elevations the snowpack is mostly stable. Two separate avalanche fatalities occurred Sunday. A backcountry skier who accessed the Clause Peak area by skis and snowmobile from the Cliff Creek Trailhead in Hoback Canyon is believed to have triggered an eight inch deep soft slab on a steep slope at an elevation of about 9,200 feet and was carried into a tree and did not survive. The second fatality was a skier on Survey Peak in Grand Teton National Park who also was carried into a tree. Our sincere condolences go out to those involved and their friends and families.
At mid and upper elevations new soft wind slabs or sloughs to two feet (or more on the west side) in depth will be easily triggered on a variety of aspects. The long, dry, cold period created excellent sliding surfaces of wind pack, sun crusts and faceted snow. Forecasted increasing winds will raise the sensitivity of slabs.
Scattered snow showers or flurries will continue into early Wednesday morning with temperatures dropping to the single digits and northwest winds around 15 miles per hour. Widespread snow will develop around daybreak Wednesday and continue into Thursday morning. Accumulations of 6 to 12 inches are expected in mountainous areas by Thursday morning with locally deeper amounts. Winds will back to westerly and increase to 25 mile per hour averages with stronger gusts and daytime high temperatures will be in the mid teens.The general avalanche hazard is expected to be MODERATE Wednesday morning and increase during the day. Backcountry travelers can expect to release soft slabs and sloughs to three feet in depth on steeper, avalanche-prone slopes at mid and upper elevations in the Tetons and up to 18 inches in depth in the Togwotee Pass and Greys River areas. Be alert to changing conditions and alter plans accordingly. Remember that small, soft avalanches can be dangerous or lethal if individuals are swept into hard objects or fall into terrain traps where debris rapidly accumulates.
