Conditions are dangerous. Large destructive slab avalanches that are likely to be un-survivable are possible on a variety of aspects and elevations. Last nights winds gusted to 75 miles per hour on the summits and from 40 to 65 miles per hour at the mid elevations. These winds are likely to have caused significantly more extensive slab development than was observed yesterday. This means skiers and riders may trigger larger slab avalanches today and get further out onto these slabs before they fail. This may be the perfect recipe for a tragic avalanche accident. Large destructive avalanches that release naturally and run full path into lower elevation run out zones are possible. Excellent route-finding skills and conservative terrain choices will be essential for safe travel in avalanche terrain.
Wind slab avalanches formed by southwest to northwest winds are likely to be triggered by skiers and riders today on steep avalanche prone slopes. At the mid and upper elevations these slabs could be up to 3 feet deep, may run long distances and may be un-survivable. At the lower elevations, pockets of wind slab up to two feet in depth could human triggered on steep wind-loaded terrain features.
Deeper persistent slab avalanches could also be triggered today by the weight of a person or the release of a wind slab avalanche that steps down to a buried weak layer of faceted snow. These very dangerous avalanches could occur on a variety of aspects and elevations. They are likely to be 3 to 6 feet deep at the mid and upper elevations and up to three feet deep at the lower elevations.
The strongest portion of the northwesterly jet stream will reside over the region through Sunday, and snowfall intensity will decrease during the day. An additional 6 to 10 inches of new snow will be possible by Sunday evening. Overnight lows in the mountains will be in the upper single digits before rising into the low teens in the afternoon. Southwesterly to westerly ridgetop winds will range from 25 to 35 miles per hour before starting to decrease in the afternoon.With the copious recent snow fall, more on the way and continued strong winds, the general avalanche hazard is expected to be High in the Teton and Southwest Trails forecast zones on Sunday. Both human triggered and natural activity will be likely. These large to very large wind slabs could easily have fatal consequences, and they have the potential to travel down into low elevation terrain. Weak layers of faceted snow persist below the recent snowfall, and deeper slab avalanches could occur naturally, be human triggered or step down from the release of a wind slab. TRAVEL IN AVALANCHE TERRAIN IS NOT RECOMMENDED DURING PERIODS OF HIGH AVALANCHE HAZARD.On Togwotee Pass, where less snow has fallen, the general avalanche hazard is expected to remain Considerable. Skiers and riders could easily trigger small to large wind slabs along with large to very large persistent slabs. Natural activity will also be possible. Excellent route-finding skills and conservative terrain choices will be essential for safe travel in avalanche terrain.
