New shallow winds slabs and older persistent slabs have some potential to be triggered by humans who venture into steep avalanche starting zones and cliff areas at the upper elevations. Avalanches are unlikely at the mid and lower elevations. Grand Targhee Resort is preparing its slopes for a Friday opening and therefor the resort is closed to uphill travel today.
At the upper elevation strong southwest to west-northwest winds have created pockets of wind slab six to 12 inches deep on leeward aspects. These shallow slabs could be human triggered in steep avalanche starting zones and in isolated areas may have some potential to step down to the October crust.
Some potential may persist for humans to trigger older slabs one to two feet in depth on steep northerly and easterly aspects that could fail on a buried layer of surface hoar that lies upon a hard melt-freeze crust that formed in October.
A brief ridge of high pressure will result in a dry period through Friday with less wind and valley inversions. On Friday skies will be partly cloudy. Temperatures will rise into the 30s in the mountains and into the 40s in the valleys. Winds will be northwest to west at 5 to 15 miles per hour.At the upper elevations instabilities associated with the October melt-freeze crust persist in steep avalanche starting zones that face north. In addition strong west-southwest winds have created pockets of shallow wind slab on leeward aspects. The general avalanche hazard at the upper elevations is expected to be MODERATE. Humans who venture into steep avalanche starting zones and cliff areas could trigger slab avalanches up two feet in depth that could fail on a buried melt-freeze crust. Avalanches are unlikely below an elevation of 8,500 feet.
