Up to 15 inches of new snow with about three quarters of an inch of moisture has fallen at the higher elevations during the past several days. At the mid and upper elevations strong winds and warming temperatures have created areas of unstable snow. Soft wind slabs have formed upon good sliding surfaces and are likely to be easily triggered by humans at the upper elevations and in pockets at the mid elevations. Some potential also exists for deeper, dense slides to fail on buried weak layers of faceted snow. Avalanches are unlikely at the lower elevations.
Wind slabs up to two feet in depth formed by northwest winds lie upon slick old snow surfaces. These soft, surface slabs are likely to be easily triggered by skiers and riders on steep wind loaded slopes and in cliff areas.
At the mid and upper elevations layers of weak faceted snow exist in the snowpack beneath the recent light density snow that fell during the past several days. Slab avalanches with depths of one to three feet could be human triggered on these buried weak layers, especially by larger triggers such like snowmachines. Areas of thin snow on very steep slopes and in cliff areas are likely trigger points.
Steady snowfall will occur overnight as a vigorous, fast moving storm system impacts the region. This scenario is expected to culminate in one last blast of snow and wind around sunrise as a strong Pacific cold front tracks across the area. Additional snow totals by Tuesday morning are expected to be up to ten inches in the Tetons and range from four to seven inches in the other ranges. Valley locations are expected to receive 2 to 5 inches. Tuesday will begin with temperatures in the 20s, heavy snowfall and strong northwest winds that will create areas of blowing snow. Conditions will moderate as the day progresses with decreasing snowfall, slowly clearing skies and diminishing winds. Temperatures at 10,500 feet will fall from 20 to 10 degrees as colder air moves into the region.Strong wind and new snow will create dangerous avalanche conditions. Natural avalanche activity is possible on a variety of aspects at all elevations. The general avalanche hazard is expected to increase to HIGH in areas with the greatest impacts from this storm system and to CONSIDERABLE in areas with lesser but significant impacts. Travel in avalanche terrain is not recommended.
