Salt River and Wyoming Ranges

Evidence of a recent natural release of a very large slab avalanche on a west aspect of Rock Lake Peak was reported yesterday. Very large slab avalanches could be human triggered on steep avalanche prone slopes in areas with poor snowpack structure. Large triggers like snowmachines and cornice drops are more likely to trigger one of these dangerous slabs. Previous tracks may not be an indication of stability. Wind slabs could also be triggered by humans in very steep terrain at the higher elevations. Wet snow avalanches are possible on very steep terrain features at the lower elevations. A careful evaluation of the snow structure and conservative terrain choices are warranted in areas which exhibit poor snow structure.

( Discussion is generated from the previous day's afternoon forecast. )Periods of snow will continue overnight. Additional accumulations of 5 to 10 inches in the mountains and 2 to 4 inches in the valleys are possible. More snowfall and cloudy skies are expected on Thursday. Temperatures will be in the upper teens and 20s in the mountains and upper 20s and 30s in the valleys. Winds will from the southwest at 10 to 20 with gusts to 30 miles per hour.Southwest winds will be forming pockets of fresh wind slab on leeward aspects along the higher ridge crests. These new slabs could build to depths of one to two feet in favored areas. On steep slopes they are likely to be sensitive to human triggers. In areas with poor snow structure dangerous deep persistent slab avalanches continue to be a serious hazard on steep avalanche prone slopes. In these areas dense thick slabs lie upon a base of well-developed faceted snow. The release of these deep slab avalanches are most likely to be initiated by larger triggers such as snowmachines. The general avalanche hazard is expected to be moderate. Conduct careful evaluations of snowpack stability and make conservation terrain choices in areas that have poor snowpack structure.