Skiers and riders could trigger slab avalanches on steep terrain features above an elevation of 8,500 feet and on isolated terrain features below that elevation. A thermal inversion exists. Temperatures at 5 am at 10,870 feet on Mt. Coffin are 35 degrees warmer than they are in the coldest valley locations. Today's sunshine and rising temperatures may increase the avalanche hazard on steep sunlit aspects. Monitor conditions for increasing hazard from this warm up and move off of and out from under steep slopes if warming conditions are significantly impacting the stability of the snowpack. Yesterday a skier triggered a large slab avalanche in the starting zones of a major avalanche path on an east aspect of Beaver Mountain. That area of that avalanche path had previously slid and had a shallow snowpack. This dangerous slide broke to the ground on faceted snow and was four feet deep.
Soft slab avalanches could be triggered by backcountry travelers in steep, wind loaded areas. These slabs are more likely to be found at higher elevations where they could have depths to three feet. At lower elevations, isolated pockets of slab could be triggered on very steep slopes. Today's sunshine and rising temperatures may to increase the sensitivity of these slabs to human triggers.
( Discussion is generated from the previous day's afternoon forecast. )The weather will be dry with a building temperature inversion. At the upper elevations temperatures will drop to around zero overnight and rise into the low 20’s during the day. In the coldest valley locations temperatures will into the negative teens overnight and rise into the 20’s during the day. Winds will stay light at 5 to 15 miles per hour and back from the northwest to the southwest.At the higher elevations wind slabs can still be triggered by skiers and snowmobilers in steep avalanche prone terrain. These slabs are generally expected to be one to three feet deep. However today a skier triggered a four, foot deep slide on faceted snow in a slide path on Beaver mountain that had previously slide. Slab avalanches could be human triggered on isolated terrain features at the lower elevations. Sunshine and warmer temperatures are likely to increase the sensitivity of these slabs to human triggers. Monitor conditions for increasing hazard on steep sunlit aspects during the warmest portion of the day. The general avalanche hazard is expected to be moderate at the higher elevations. The hazard is expected to be low below an elevation of 9,000 feet in the Teton area, 8,500 feet in the Greys River area and 8,000 feet in the Togwotee Pass area.
