Tetons

At the upper elevations yesterdays strong westerly winds may have formed small pockets of shallow wind slab, less than a foot in depth. These small wind slabs could pose a hazard above cliff areas and terrain traps and in steep couloirs and chutes. In steep upper elevation avalanche paths the interface between a late October snow surface and snow that fell in early November produced large slabs avalanches on east and northeast aspects ten days ago. This layer warrants careful assessment and consideration with respect to terrain choices. Grand Targhee Resort is closed to uphill travel while preparations are in progress for their opening on Friday.

The National Weather Service has issued a Winter Strom Warning from midnight tonight through Friday afternoon. The leading edge of a major winter storm will move into western Wyoming tonight. Like most of the storms that have hit us this season this storm will favor the Teton, Togwotee Pass and the northern portion of the Greys River area. The freezing level is anticipated to rise to an elevation of 7,000 feet by morning. Rain is likely in the valleys, a mix of rain and snow is expected between 7,000 and 8,000 feet. At the higher elevations snowfall will develop overnight and intensify during the day and into the evening. Upper elevation accumulations are forecast to be 4 inches by noon, another 6 inches by midnight with another 9 inches by noon on Friday. West to southwest winds at 25 to 35 with gusts to 50 miles per hour will accompany the snowfall. Temperatures will be in the mid and upper 20s at 10,000 feet and in the 30s and 40s in the valleys.New snow and winds will increase the avalanche hazard as the day progresses. The heaviest snowfall is expected on Thursday evening and into Friday. New wind slabs will form on leeward aspects and gain depth and volume as this storm develops and intensifies. The general avalanche hazard is expected to rise to MODERATE during the day and is likely to increase to CONSIDERABLE in the most favored locations as snowfall intensity increase to rates of over an inch per hour by evening.