Nearly a foot of snow has fallen and more is expected today. Strong west winds have accompanied this snowfall and have formed wind slabs at the mid and high elevations. Backcountry riders and skiers could easily trigger these slabs and have an increasing potential to trigger older and harder slabs that lie upon buried weaknesses. At the low elevations caution is also advised as new snow has fallen on a weak faceted snowpack. Areas that previously had inadequate coverage could now see loose snow sluffs or pockets of soft slabs in steep terrain. Yesterday there were multiple skier triggered avalanches in the Teton Range and one skier had a close call when he was partially buried to his waist. An avalanche watch is being issued for the weekend as a potent storm system approaches and dangerous avalanche conditions are expected.
Strong winds that have blown from the west-southwest to the northwest have formed wind slabs on steep leeward slopes. These slabs could be easily triggered by backcountry travelers today with depths to two feet this morning. These slabs are expected to increase in size and sensitivity as snowfall and continued winds continue to load them throughout the day.
Persistent layers of faceted snow lie in the snowpack. Rapid loading since yesterday has increased the chances to trigger these older hard slabs that could reach depths to as much as four feet. These older dangerous hard slabs could be triggered after initiation of a wind slab, by a single person hitting a weak spot, or by larger loads such as snow machines.
( Discussion is generated from the previous day's afternoon forecast. )Snow is to continue this evening as the system pushes through the area. Another weaker disturbance is to bring periods of snow on Friday. An additional six inches of snow could fall by tomorrow evening. Highs tomorrow are to be in the upper teens. Winds tomorrow are to be westerly and strong with twenty to thirty five mile per hour averages. The general avalanche hazard will be Considerable above 7500 feet and Moderate below that elevation. The continued snowfall is to increase the size of new wind slabs that have formed on steep leeward slopes. These slabs lie on slick sliding surfaces and weak snow and could be easily human triggered with depths of one to two feet. At lower elevations, new snow lies upon a weak and faceted snowpack in steep shaded terrain where loose snow sluffs or pockets of soft slab could be triggered.
