A few details from Friday’s snowmobile fatality have trickled in. It appears that the event took place east of Upper Palisades Lake on a south facing slope around an elevation of 9,000 feet. Four snowmobilers were caught; three were able to self-rescue, and one was fully buried. Yesterday in the Snake River Range, a snowmobiler triggered a 30 inch deep pocket on an east facing slope at 8,100 feet. Human triggered avalanche activity was also reported in the Tetons on Saturday.Above 7,500 feet, skiers and riders could trigger small to large wind slabs in steep, leeward terrain. Backcountry travelers could also trigger large to very large persistent slabs on a variety of aspects and elevations. These dangerous slabs could step down from the release of a wind slab. Mountain temperatures are starting out around 10 degrees warmer than yesterday, and any extended periods of sunshine could increase the likelihood of triggering these slabs on sunlit aspects. Careful snowpack evaluation and conservative terrain choices will be your best tools for staying safe in avalanche terrain. Skiers and riders still have some potential of triggering small to large slab avalanches below 7,500 feet.
Strong northwesterly ridgetop winds were sustained on Saturday, and wind slabs continued to form on leeward slopes. Backcountry travelers could trigger these slabs with depths of one to two feet in steep, wind loaded terrain.
On steep avalanche prone slopes, large persistent slab avalanches could fail on buried weak layers of faceted snow. These dangerous slabs could be up to four feet deep above 7,500 feet. Below 7,500 feet, slab depths are expected to range from one to two feet. These slabs could be triggered directly by the weight of a single person or indirectly after the release of a wind slab.
( Discussion is generated from the previous day's afternoon forecast. )Expect mostly cloudy to overcast skies on Sunday as the flow aloft backs to the northwest and brings some limited Pacific moisture to the region. During the day, a few light flurries will be possible. Overnight lows in the mountains will be in the low teens before rising into the low to mid 20s in the afternoon. Northwesterly ridgetop winds will back to the west at 10 to 20 miles per hour.The general avalanche hazard is expected to remain Considerable above 7,500 feet on Sunday. On steep, leeward slopes impacted by recent winds, skiers and riders could easily trigger wind slabs ranging in depth from one to two feet. Persistent weak layers of faceted snow remain a concern, particularly in the Togwotee Pass forecast zone and other areas that have shallow, faceted snowpacks. Slabs failing on these weak layers might be up to four feet deep, and could either be triggered directly by backcountry travelers or step down from the release of a wind slab. On Sunday, careful snowpack evaluation and conservative terrain choices will be your best tools for staying safe in avalanche terrain. Below 7,500 feet, skiers and riders will continue to have some potential of triggering slab avalanches up to two feet deep.
