Tetons

Dangerous avalanche conditions exist. This is especially true in the northwest portion of the forecast area where the most snowfall occurred. At Grand Targhee resort, 15" of snow fell overnight. This new snow was accompanied by moderate to strong winds and can be easily triggered by backcountry riders and skiers today in steep terrain at the upper elevations. Avalanches can also be triggered involving new snow at the mid elevations. At low elevations, avalanche activity is unlikely however very steep terrain that received higher snowfall amounts could produce avalanches in isolated areas.  Making conservative terrain choices by avoiding very steep terrain is the best way to avoid this type of avalanche concern caused by rapid loading. 

This storm clearly favored the northwest portion of the Tetons. When snowfall amounts vary that significantly between nearby stations such as Targhee and Surprise Meadows, knowing what specific drainages received particularly high snowfall amounts is difficult.  Although the area around Targhee is expected to have the most sensitive and larger slab problem, other areas can also have received high snowfall rates and be equally sensitive. In the south Tetons where it appears that 6-7" of new snow fell, wind slabs to over a foot are expected to be sensitive in very steep, leeward terrain. Last week's strong northeast winds following the storm provided for atypical snow surface so evaluating the interface of the recently buried snow surface and the new snow will provide a lot of insight in evaluating slope stability. The older persistent problems, particularly the one buried on January 26th, are not thought to be a concern at this time.