Continued snowfall and very strong winds will quickly form new surface slabs as well as rapidly add load to persistent weak layers that are buried within the snowpack. The chance to trigger either of these avalanche problems will increase throughout the day as dense snow accumulates and winds veer from the southwest to the northwest. Dangerous avalanche conditions exist and natural avalanche activity will be possible at the mid and upper elevations by the end of the day. Cautious route finding and conservative decision making is the best way to avoid involvement in hard to predict persistent slab avalanches.
New snow is forming wind slabs over faceted snow, surface hoar and crusts above 8000 feet. These slabs will increase in size and sensitivity as the day progresses and could have depths to a foot by later this afternoon.
The relatively wet and heavy snow that is falling will quickly add stresses to buried weaknesses in the snowpack. Although the level of weakness varies by location, these layers can generally be found at all elevations and most aspects. Release of these slabs is hard to predict and failure could occur after a slope is tracked when a weak or thin spot on a slope is impacted. By the end of the day, potential slab depths could reach five feet at the higher elevations and two feet at low elevations where the snowpack structure is poor.
Dryer, colder air is moving in. Northwest winds will decrease overnight. Clearing skies are expected on Thursday with some lingering snow showers possible over the higher elevations. Little to no accumulation is anticipated. Temperatures will be in the single digits and teens in the mountains and will rise into the 20s in the valleys.Today’s strong winds and new snow fell upon surface hoar that was widespread and well developed. This storm also increased and redistributed the load on buried weak layers that persist in our snowpack on a variety of aspects at all elevations. Skies and riders who venture into steep, wind loaded avalanche starting zones are likely to triggered dense wind slabs 6 to 18 inches deep. Dangerous slab avalanches that could fail on deeply buried weak layers could also be triggered by humans. These persistent slab avalanches are likely to be 2 to 4 feet deep, destructive and potentially un-survivable. In the Teton and Greys River areas the general avalanche hazard is expected to be considerable above an elevation of 7,500 feet. In this terrain conditions are dangerous. A careful evaluation of the snowpack and conservative terrain choices are essential for safe travel in avalanche terrain. The general avalanche hazard is expected to be moderate at the lower elevation in these areas and in the Togwogtee Pass area. In this terrain heightened avalanche dangers exist on avalanche prone slopes. where humans could trigger slab avalanches 1 to 3 feet deep.
