Dangerous avalanche conditions exist. Up to a foot of new snow has fallen in the past 24 hours and over two feet of new snow with nearly three inches of moisture has fallen since Tuesday. Southwest winds veered to the west and increased overnight. This snow has been falling on an early season snowpack that has poor structure. A weak layer of faceted snow that was buried on Thanksgiving is widespread and may become unstable due to this new load. At the mid and upper elevations human triggered avalanches are likely in steep terrain. Natural avalanche activity is possible. Avalanche types include loose snow sloughs in cliff areas and steep terrain, fresh soft wind slabs along the leeward side of higher ridge crest and deeper slab avalanches that can fail on a persistent weak layer of faceted snow and crust. Careful snowpack evaluations and conservative decisions are essential for safe travel in avalanche terrain. Watch for areas of unstable snow on isolated terrain features at the lower elevations.
At the mid and upper elevations slab avalanches one to three feet in depth are likely to be triggered by humans in steep wind loaded avalanche starting zones and could release naturally.
Some light snow and flurries will continue early this evening across the northern portions of our forecast areas. Skies are expected to be mostly clear in the morning. Increasing clouds are forecast during the afternoon. Temperatures will be in the single digits and teens. Winds will veer to the east and be light at 5 to 15 miles per hour. Snowfall since Tuesday has favored the Tetons and Southwest Trails areas. In all areas the snowpack structure is poor. A persistent weak layer of faceted snow has a history of producing avalanches at the mid and upper elevations. The recent new snow has increased the load on that problem layer. At those elevations in the Teton and Southwest Trails areas the general avalanche hazard is expected to be CONSIDERABLE and slab avalanches 1 to 3 in depth are likely to be triggered by humans in steep terrain. At those elevations in the Togwotee Pass area the general avalanche hazard is expected to be MODERATE. Slab avalanche up to two feet in depth could be triggered by humans on steep slopes. Avalanches are unlikely below an elevation of 7,500 where the general avalanche hazard is expected to be LOW.
