At the upper elevations and in steep north facing terrain at the mid elevations two feet of light density has loaded a persistent weak layer of faceted snow that lies on a hard rain crust. Poor visibility has limited avalanche observations, however large slab avalanches were reported to have released naturally and on approach in steep terrain east of the boundary of the Grand Targhee Ski Resort yesterday. Similar events are possible today. Large avalanches are unlikely in areas where the the October rain crust is not present at the base of the snowpack. A conservative approach to suspect terrain and expert terrain evaluation skills are essential for safe travel in avalanche terrain. Grand Targhee Ski Resort and the Jackson Hole Mountain Resort are closed to uphill traffic as resort workers conduct avalanche hazard mitigation efforts and prepare to open those resorts.
Dangerous slab avalanches two to four feet in depth could be human triggered or release naturally in response to continued wind loading on east through north to west facing terrain at the upper elevations and in steep north facing avalanche paths at the mid elevations.
Brief clearing overnight could result in areas of patchy morning valley fog and temperature inversions. Clouds will increase during the day and likely bring a period of light snowfall to the mountains. Temperatures will remain in the single digits and teens. Winds will back to the west and decrease to speeds of 10 to 15 miles per hour.Large human triggered slab avalanches will continue to be a significant hazard at the upper elevations where there is a persistent weak layer near the base of the snowpack that lies upon an October rain crust. These dangerous slabs are up to three feet deep and will continue to be sensitive to the weight of a person for an extended period. Avalanches are unlikely in areas where this persistent weak layer on a hard crust combo does not exist. The general avalanche hazard is expected to be CONSIDERABLE at the upper elevations in the Teton area and MODERATE at the upper elevations in the Togwotee Pass and Greys River areas. The hazard is expected to be LOW at the mid and lower elevations.
