Riders and skiers should be aware of two types of avalanche concerns in the backcountry today. Wind slabs formed by recent snow and strong winds lie at the mid and high elevations. Also, on certain aspects at the high elevations the possibility continues to trigger very large and dangerous avalanches involving weak snow near the base of the snowpack. Although the likelihood of triggering one of these deep instabilities has lessened, make no mistake that the weakness remains present and failure is still possible to larger triggers such as snow machines or if a weak trigger point is crossed. Evaluate snow and terrain carefully. At low elevations, avalanches are unlikely except for in isolated pockets of small soft slab.
Recent snowfall and strong south-southwest to west winds have formed soft slabs in steep leeward slopes near ridgelines and under cliff areas where drifting snow accumulates. These slabs could be triggered in very steep terrain with depths of one to three feet.
At the upper elevations deep hard slabs continue to be a concern on west through north to east aspects. Surviving one of these slabs is unlikely as they could have depths to eight feet and be very destructive.
Inversion conditions and patchy fog are expected Friday morning. Mountain temperatures should be near ten degrees in the morning, with valley temperatures below zero. By noon temperatures should reach the upper teens to low twenties under mostly clear skies. At that point an upper lever trough moving from the west to southeast, combined with arctic air, should bring snowfall to the area by evening. This snowfall should continue through most of Friday night. The general avalanche hazard in the Tetons will be Moderate at the mid and high elevations, and Low at the low elevations. In the Togwotee Pass and Southwest Trails areas, the rating will be Considerable above 9000 feet, and Moderate below that elevation. Although the ratings vary, the avalanche problems are generally the same in all areas. Weak snow near the base of the snowpack persists on west, north and east aspects above 9000 feet. A single rider or skier could still trigger large and dangerous avalanches involving this layer in all forecast areas, although they are less likely to be triggered in the Teton area, mainly due to greater snow depths. Additionally, wind slabs to two feet could be triggered in steep, wind-loaded terrain.
