Tetons

At the upper elevations, recent snowfall and strong winds have formed slabs that could be triggered by backcountry enthusiasts today. These slabs will be most sensitive in steep terrain where they have formed on the old snowpack, as the older snow is comprised mainly of hard crusts and facets, particularly on higher, shaded terrain. At mid elevations, the hazard remains Low as less snow has fallen and the old weak snowpack is less prevalent. New snow lies directly on the ground at the low elevations where avalanche hazard has yet to develop. Early season conditions exist and caution is advised in both avoidance of this slab hazard as well as in negotiating safe routes in a shallow snowpack.

A break in the snowfall intensity that began during the afternoon hours will continue into the evening. Snowfall will pick up from south to north after mid-night and should bring several inches of new snow to the region by sunrise and another couple of inches of snow before noon. Periods of moderate to heavy snowfall are likely in the afternoon. Temperatures will be in the teens overnight and will rise into the upper 20s and 30s on Friday. South to southeast winds be light at 5 to 15 miles per hour The general avalanche hazard is expected to increase to CONSIDERABLE at the upper elevations and to MODERATE at the mid elevations. On steep avalanche prone slopes at the upper elevations human triggered slab avalanches are likely and natural avalanche activity is possible. These slabs will fail on weak and firm old snow surfaces with depths to 30 inches and could gouge down into older layers of faceted snow. At the mid elevations human triggered slab avalanches are possible in steep avalanche paths with aspects that have a northerly component. These slab avalanches could be up to two feet deep. Rising temperatures and increasing snowfall intensities in the afternoon are likely to increase the avalanche hazards. The combined effects of warming and loading will increase the potential for human and naturally triggered avalanche activity. Monitor conditions for increasing hazard. Conservative terrain choices and a careful evaluation of the structure of the snowpack with an emphasis on the presence of buried persistent weak layers is warranted. More snow means tomorrow’s avalanches will be larger and more dangerous. Avalanches are unlikely in areas where the snow that has fallen since early Monday morning has accumulated on mostly bare ground. In these areas the general avalanche hazard will be low.