Wind slabs have formed over the past week and continue to form with new snow and strong southwest winds. These slabs have released naturally and will be sensitive to human triggers today on loaded terrain features. Addition hazard exists in the form of older harder slabs that lie on persistently weak snow near the base of the snowpack. These deeper instabilities could still be triggered by a single rider or skier or by one of the smaller wind slab avalanches once it is initiated. Avalanches are unlikely below an elevation of 7,500 feet.
At the upper elevations several days of southwest to northwest winds have created areas of surface slab. These slabs could have depths of eight inches to greater than two feet. These slabs could be human triggered in steep avalanche starting zones and cliff areas.
Hard slabs, with depths to four feet, lie upon persistent weak layers of faceted snow on a variety of aspects. A snowmobile, the weight of a single skier or the release of wind slab could trigger one of these hard slabs. Previous tracks and the lack of recent avalanche activity are not indications of stability.
( Discussion is generated from the previous day's afternoon forecast. )Snow is to develop overnight and continue on Thursday with the highest precipitation rates expected between 5am and 11am. By the evening four to six inches are expected in the Tetons with higher amounts in localized areas and slightly lower accumulations are expected in the Togwotee and Southwest trails areas. Winds are to be southwesterly with 15-25 mph averages and temperatures should be slightly cooler with highs near twenty degrees.The general avalanche hazard is expected to be Moderate above 7500 feet and low below that elevation. New snowfall and southwest winds are expected to form new wind slabs as well as add load to existing wind slabs. In any higher terrain, accumulating snowfall will add load to the slabs lying on persistent weak layers. If significant enough snowfall occurs these slabs could become more sensitive to triggers, and these potential triggers include the easier to trigger wind slab avalanches.
