Tetons

New snow and wind are adding to an existing problem of soft wind slabs that lie upon weak snow layers and hard crusts. At the mid and high elevations skiers and riders have the potential to trigger these slabs in wind loaded areas. This hazard is more prevalent at the higher elevations due to recent snowfall and will increase as the day progresses and both the size and sensitivity of the slabs increase. At low elevations, avalanches are unlikely except for small slides on isolated features. Monitor weather factors today, evaluate snow and terrain carefully, and identify wind loaded features for safe backcountry travel.

The National Weather Service has issued a Winter Storm Warning effective until noon on Saturday. As the low pressure system moves from the northwest to the southeast, the Tetons and the Southwest Trails forecast zones are expected to have higher snowfall amounts. By Saturday evening, these areas could see an additional 10 to 15 inches of light density snow. Overnight lows in the mountains will remain in the singled digits overnight before rising into the low teens during the day. Westerly ridgetop winds will veer to the northwest at 20 to 35 miles per hour.The general avalanche hazard is expected to be CONSIDERABLE in the mountains on Saturday as continued snowfall and strong ridgetop winds increase the load on faceted weak layers that formed during the mostly dry period from the first half of December. Below this faceted snow, stout crusts from the end of November will provide good sliding surfaces, and backcountry travelers are likely to trigger slab avalanches ranging in depth from one to three feet. Natural activity will also be possible. A conservative approach to terrain management will be essential for safe travel in avalanche terrain on Saturday. If more snowfall than forecasted materializes and strong winds continue, the hazard at the upper elevations could rise to HIGH.