Two large slab avalanches were unintentionally triggered by skiers yesterday. One occurred in the Greys River area on a southeast aspect of Pow Wow Peak on Grey Back Ridge. The other occurred on the east face of Mt. Taylor near Teton Pass. Being caught in either of these slides could have been deadly. Similar events are possible today. At all elevations large slab avalanches could be triggered by the weight of a person on steep avalanche prone slopes. Conservative choices are essential for safe travel in avalanche terrain. Most recreational avalanche fatalities occur during periods of considerable or moderate avalanche hazard.
Buried layers of faceted snow exist in the snowpack. Large persistent slab avalanches could fail on these layers with depths from 2 to 4 feet at the higher elevations and up to two feet deep at the lower elevations. These dangerous slabs could be triggered by the weight of a single person.
( Discussion is generated from the previous day's afternoon forecast. )Light snowfall will develop and become steadier by midnight. Accumulations of 2 to 4 inches in the mountains and 1 to 2 inches are possible before daybreak. Periods of light to moderate snowfall could bring another three inches of new snow to the area during the day. Temperatures will be in the single digits and teens. Winds will be from the southwest to south at 15 with gusts to 25 miles per hour.Humans could trigger large slab avalanches in steep avalanche starting zones and on steep slopes with poor snow structure. These slab avalanches could be two to four feet deep and could occur of a variety of aspects at all elevations. Slope specific stability assessment is difficult in these conditions. The consequences of triggering a large slab avalanche are likely to be severe. Conservative terrain choices are essential for safe travel in avalanche terrain. The general avalanche hazard is expected to be moderate at all elevations. Most recreational avalanche fatalities occur during periods of considerable or moderate avalanche hazard.
