New snow and strong winds have formed wind slabs on a variety of sliding surfaces including sun crusts and faceted snow. Backcountry riders and skiers could easily trigger these slabs in steep leeward terrain at the mid and upper elevations. Since Tuesday night in the Tetons, there have been about 20 inches of snow with 2 inches of snow water equivalent and strong west to northwest winds with gusts to 62 miles per hour. Last night and early this morning WYDOT put avalanche debris across the Teton Pass roadway from 3 separate slide paths. Along with the wind slabs, weak snow near the base of the snowpack could also fail, resulting in large persistent slab avalanches. Larger triggers such as cornice drops, snow machines, or a surface wind slab could trigger such an event. At lower elevations, soft slabs could be triggered in steep wind loaded avalanche starting zones. Cautious route-finding and conservative decision making are essential for safe travel in avalanche terrain today.
Strong west to northwest winds continue to transport snow into avalanche starting zones on leeward aspects. These slabs will be sensitive to backcountry travelers on a variety of aspects. Slab depths could be one to three feet with the deeper depths favoring the upper elevation avalanche starting zones.
Above 8000 feet, weak snow lies near the base of the snowpack. This weakness is most likely to be found on northwest through northeast aspects, although it does exist on other aspects at the higher elevations. New snow is stressing this layer, making it more susceptible to failure. If triggered, it would be difficult to survive one of these hard slab avalanches that could have crown depths up to five feet in depth.
Skies will be mostly cloudy with periods of light snowfall. The higher elevations may receive 3 to 6 inches during the next 24 hours. Valley locations are likely to receive less than an inch. Temperatures will be in the teens and 20's. Winds will be from the west to southwest with gusts from 30 to 40 miles per hour on the peaks. Conditions are dangerous at the mid and upper elevations. Large slab avalanches can be triggered by humans on steep slopes. These dangerous slides could be 2 to 5 feet deep. Up there the general avalanche hazard is expected to be considerable. Some potential remains for humans to trigger smaller slab avalanches on isolated terrain features at the lower elevations (below 7,500 feet). Down there the general avalanche hazard is expected to be low.
