Increasing winds are forecast to create areas of blowing snow at all elevations. These winds will increase the avalanche hazard and create dangerous conditions. New wind slabs are forming on a snowpack with poor structure and persistent weak layers. Natural avalanche activity and human triggered slab avalanches are likely on a variety of aspects. Expert terrain analysis skills are essential for safe travel in avalanche terrain. Avalanches are less likely below an elevation of 7,500 feet. Down there pockets of wind slab may be triggered by humans on very steep terrain features. In these locations a careful elevation of the snowpack and terrain is warranted.
Strong winds will be forming new slabs on leeward aspects. These slabs are likely to be one to two feet in depth and are expected to be easily triggered by humans who venture into steep wind loaded avalanche starting zones and could release naturally.
Today's loading event could cause large slab avalanches to release naturally and be easily triggered by humans on persistent weak layers that formed earlier in the season. These dangerous slab avalanches could be 2 to 4 feet deep and could be destructive.
( Discussion is generated from the previous day's afternoon forecast. )After a brief lull, another more impactful storm will move into the area. Snowfall will increase after midnight and become heavy from around 2AM to 11AM. This system will bring another 6 to 12 inches of snow to the region. It will be accompanied by steadily increasing southwest to west winds. On Monday winds will frequently gust to 50 to 60 miles per hour along the high ridges throughout the daylight hours. Valley winds will steadily increase to sustained speeds of 20 with gusts to 30 miles per hour from sunrise into the afternoon. The snowfall and winds are forecast to decrease around sunset. Temperatures will be in the teens in the mountains and in the upper teens to upper 20s in the valleys. There were two avalanche fatalities in the Rocky Mountain region yesterday. A snowmobiler died west of Choteau, Montana and a backcountry skier died near Red Mountain Pass in southwest Colorado.Very strong sustained winds and new snow will create dangerous avalanche conditions at all elevations in all of our forecast areas. Blowing and drifting snow will cause whiteout conditions and rapidly load a snowpack with poor snow structure and persistent weak layers. Natural avalanche activity is likely on a variety of aspects at all elevations. Large slab avalanches are likely and very large slab avalanches are possible. The Wyoming Department of Transportation will close the highway over Teton Pass at 3AM for the purpose of conducting avalanche hazard mitigation efforts. Avalanches may impact highways on that road and in the river canyons during this storm. On Monday the general avalanche hazard is expected to high in the Teton and Greys River/Southwest Trails areas. Travel in avalanche terrain is not recommended. Large to very large natural avalanches are likely. The general avalanche hazard is expected to be considerable in the Togwotee Pass area where conditions will also be dangerous. Large human triggered avalanches are likely and large natural avalanches are possible. Expert terrain analysis skills are essential for safe travel in this area.
