The National Weather Service has issued a winter storm warning through Monday morning. Temperatures will warm throughout the storm creating an upside down snowpack. During the day, light density snow and strong southwesterly to westerly ridgetop winds will continue to build new soft slabs in leeward starting zones at the upper elevations. Backcountry travelers could trigger these shallow slabs, along with loose snow sluffs. Wind loading will also add weight to persistent slabs, which will become more susceptible to failure as the day progresses. Monitor conditions closely, and be willing to alter your plans if circumstances warrant.
On steep slopes that have not experienced recent avalanche activity, backcountry travelers could trigger large slab avalanches that fail on persistent weak layers. These slabs, with depths of two to four feet, could release to the ground.The likelihood of triggering these slabs will increase during the day with the additional load of the new snow.
( Discussion is generated from the previous day's afternoon forecast. )Zonal flow will develop sometime before Friday morning. This change in the weather pattern will bring moderate to heavy snow showers, strong winds and warming temperatures. Six to twelve inches of new snow could accumulate by Friday evening. Southwesterly ridgetop winds will increase to 25 to 35 miles per hour. Overnight lows will hover near zero before rising into the mid teens during the day.On Friday, the general avalanche hazard is expected to be MODERATE in the Tetons and Greys River area, and CONSIDERABLE in the Togwotee Pass area. New snow, combined with strong westerly ridgetop winds, will create new wind slabs on leeward slopes. These new slabs could be triggered by backcountry travelers in steep, wind-loaded starting zones. As snowfall accumulates throughout the day, the likelihood of triggering these slabs will increase as they grow in depth and volume. This scenario will also add weight to existing weak layers beneath the new/old snow interface. Monitor conditions closely, and be willing to alter your plans if circumstances warrant.
