Nearly 70 inches of snow fell in the upper elevations of the Tetons in just over a week. Warm temperatures continue to drive rapid settlement of this snow. In colder terrain that faces northwesterly to easterly, this recent snow lies upon old snow surfaces at the high and upper portion of the mid elevations. On steep wind loaded slopes in this terrain, the potential continues for skiers or riders to trigger pockets of slab. If triggered these slabs have the potential to seriously injure someone given the shallow snowpack and the associated hazards. Below 8500 feet avalanches are unlikely except for the chance for wet loose slides to occur this afternoon, particularly on very steep banks and road cuts. As the Grand Targhee Resort prepares to open on Friday, the mountain will be closed to uphill travel.
In steep terrain, where wind blown snow lies on old crusts and depth hoar the potential continues to trigger soft slab avalanches with depths of one to three feet. These slabs will be more sensitive this afternoon when they are further weakened by increasing temperatures and sunlight.
The next system will bring precipitation back to the area around sunrise. Temperatures will be much warmer with this system and although only snow is expected in the higher elevations, a mix of snow and rain is likely at the lower elevations. Several inches of accumulation could occur in the mountains by midnight on Wednesday with minimal accumulations in the valleys. Winds are to be southwesterly with 15 to 20 mile per hour averages. The general avalanche hazard will be Moderate above 9000 feet. In steep wind loaded terrain above that elevation, the slight chance continues for slabs to be human triggered. These slabs could be shallow, involving new and wind-blown snow or in some areas, could release down to the old snow surface with depths to three feet in the Tetons, or two feet in the Togwotee or Southwest Trails areas. Avalanches below 9000 feet are unlikely. Remember the snowpack is still shallow and many hazards exist. Use caution in order to enjoy a long winter season. Uphill hiking is not currently allowed at either Grand Targhee or Jackson Hole Ski Resorts as they prepare for upcoming operations.
