Salt River and Wyoming Ranges

Persistent slabs continue to pose a serious threat to backcountry travelers. On Saturday a snowmobiler triggered a hard slab on Commissary Ridge in the Smiths Fork area that was 30 inches deep and failed on faceted snow near the ground. Recent new snow and west-northwest winds have increased the load on these dangerous slabs and their sensitivity to human triggers. Conservative terrain choices are warranted. Avalanches are unlikely below an elevation of 7,500 feet.

( Discussion is generated from the previous day's afternoon forecast. )Thermal inversions are expected to develop overnight and trap areas of fog in the valley until around noon. Skies will be mostly sunny in the mountains. Temperatures will drop into the single digits in the mountains and into the single digits below zero in the valleys. Daytime highs will rise into the 20s. Winds will be west to northwest at 10 to 20 miles per hour.Isolated pockets of wind slab less than a foot in depth could be triggered in cliff areas at the highest elevations. The primary hazard at the mid and upper elevations is hard slabs that lie upon persistent weak layers of faceted snow. In general these slab are more likely to be triggered in areas where the total snow depth is less than 50 inches deep and a little less little likely to be triggered but more consequential in areas with a deeper snow cover. These slabs could be 30 to 60 inches deep. The unstable areas are isolated but can be found on all aspects above 7,500 feet. We think these dangerous slabs could still be triggered by the weight of a single person but are more likely to be triggered by snowmobiles. The general avalanche hazard is expected to be MODERATE at the mid and upper elevations and LOW below an elevation of 7,500 feet where avalanches are unlikely.