We are sad to report that a snowmoblier was killed in an avalanche near Sheep Pass yesterday. Our sincere condolences are extended to this person’s family and friends. Current information is limited. Search & Rescue personnel worked into the evening to recover the body. They reported that it occurred in the Sheep Pass area on an east facing slope and that the rider deployed an airbag but did not survive. Snow that fell during the past week lies upon persistent weak layers. The weight of a single person can trigger a slab avalanche on steep avalanche-prone terrain. At the mid and upper elevations these slab avalanches are large enough to fully bury or seriously injure a person. At the lower elevations, small avalanches are possible on steep slopes. This type of avalanche hazard is best managed by terrain assessment skills and conservative terrain choices. Evaluate steep slopes carefully and anticipate the potential consequences of triggering a large slab avalanche or a slab avalanche of any size in terrain traps or on slopes with low snow hazards that can cause serious trauma.
At the higher elevations large slab avalanches formed by southwest to west winds could be human triggered on steep avalanche prone slopes. These slabs could be two to three feet deep. Slab avalanches triggered below an elevation of 7,500 feet are likely to be a foot deep.
( Discussion is generated from the previous day's afternoon forecast. )Overnight, a transitory ridge of high pressure will build ahead of a fast-moving short wave trough. Cloud cover is expected to increase, and by tomorrow morning, skies should be mostly cloudy. Light snowfall will develop across Western Wyoming with accumulations of one to four inches. Mountain temperatures will be in the teens and valleys should climb into the twenties. Westerly ridgetop winds are expected to be 15 to 20 miles per hour with higher gusts. The general avalanche hazard above 8,000 feet is expected to be Moderate. Skiers and riders could trigger slab avalanches one to two feet deep, where these slabs lie over persistent weak grains. The snowpack structure across the forecast area varies, and where a slab has formed dangerous avalanche conditions could exist. Below 8,000 feet, where large grain facets and buried surface hoar continue to be reactive, the small soft slabs will likely be isolated to terrain features steeper than 35 degrees. Careful terrain management is essential as the snowpack continues to adjust to the new load.
