Conditions remain dangerous at the mid and upper elevations. A snowmobiler triggered a slab avalanche east-northeast of Grouse Mountain two days ago and was reported to have been partially buried but not injured. Another slide was triggered by a snowmobiler three days ago in the Game Creek area southeast of Togwotee Mountain Lodge. Human triggered avalanches are likely on steep slopes. Conservative terrain choices are essential for safe travel in the mountains today. Avalanches are unlikely below an elevation of 7,500 feet.
Persistent slabs up to two feet in depth lie upon a base of weak, faceted snow. These dangerous slabs could be triggered by the weight of a single person on a variety of aspects and propagate across terrain boundaries. Persistent slab avalanches can remain unstable for days or weeks and pose a significant hazard to backcountry users.
( Discussion is generated from the previous day's afternoon forecast. )Western Wyoming is currently sitting between two weather systems. A strong low pressure system that is moving east into the high plains and an approaching Alberta Clipper type weather system. This system will bring clouds and some light snowfall to the region on Wednesday and Wednesday evening. Total new snow accumulations of 2 to 5 inches are likely from this system by Thursday morning. This system will favor the northern portion of our forecast areas. Temperatures will remain in the single digits and teens. Winds will be mostly from the west at 15 to 20 miles per hour with higher gusts.Our snowpack remains unstable as it struggles to adjust to the recent load. It is most sensitive to human triggers in the Togwotee Pass and Greys River area however the weight of a single person could trigger a large slide in the Teton area. The problem is weak layers of faceted snow beneath the recent new snow. Collapses and cracking are indicative of this instability and a warning to avoid steep terrain. The general avalanche hazard is expected to be CONSIDERABLE in the Togwotee Pass and Greys River area and MODERATE in the Teton area. A conservative selection of terrain is essential in all areas.
