Very dangerous avalanche conditions exist. Very strong ridgetop winds along with ample amounts of new snow have formed large wind slabs in leeward terrain at all elevations. Human triggered and natural avalanche activity is likely. Weak layers of faceted snow are common below these slabs, and avalanches could initiate on or step down to these layers. If a rain on snow event occurs at the lower elevations, the likelihood of natural activity will quickly increase. Roof slides will also be possible. TRAVEL IN AVALANCHE TERRAIN IS NOT RECOMMENED.
Over the past 24 hours, southwesterly ridgetop winds have ranged from 20 to 35 miles per hour with gusts to 55. Over a foot of dense new snow has accumulated during the same time period, and close to 30 inches of snow has fallen in the past three days. This scenario will make human triggered and natural avalanches up to three feet in depth likely at all elevations and aspects.
The National Weather Service has issued a Winter Storm Warning beginning midnight on Sunday through 11 AM on Tuesday. Light snow showers will develop overnight before snowfall intensity increases during the day. Overnight lows in the mountains will be in the mid teens before rising into the low 20s in the afternoon. Southerly to southwesterly ridgetop winds will increase to 30 to 40 miles per hour.The general avalanche hazard is expected to be Considerable Monday morning and will increase during the day as high winds and snowfall create new wind slabs. These slabs, which could reach depths of a foot by Monday evening, will form on dense snow and graupel. Weak layers of faceted snow that formed in January are common below these slabs, and avalanches could initiate on or step down to these layers. The chance of triggering full depth avalanches lingers on northerly aspects above 9,000 feet in the Togwotee Pass and Greys River forecast zones.
