At the upper elevations, backcountry travelers could trigger small pockets of winds slab in steep, wind loaded terrain. Yesterday in Granite Canyon north of the Jackson Hole Mountain Resort, a skier triggered a small wind slab in Mile Long Couloir. Similar events are possible today. These slabs could entrain loose snow and increase in volume. Although these wind slabs pose a threat, the primary concern is still the persistent deep slab avalanche. While the probability of triggering these large to very large deep slabs becomes less likely, the consequences are very high. There will be no obvious signs of instability until the avalanche is triggered. This will most likely occur in problem areas where the snowpack or slab is thin. Mostly stable snow exists below 7,500 feet.
Above 9,000 feet, westerly ridgetop winds have formed shallow, soft wind slabs on leeward slopes. These slabs have developed upon settled snow surfaces, sun crusts, and surface hoar. Backcountry travelers could trigger these slabs with depths between 6 and 12 inches in steep, wind loaded terrain.
Persistent weak layers of faceted snow that formed during extended dry periods in November and December continue to be a significant threat to backcountry travelers. Above 7,500 feet, these slabs could be triggered with depths ranging from four to seven feet. Below 7,500 feet, skiers and riders might be able to trigger an isolated pocket of a slab with depths between one and two feet.
Light snowfall overnight and into tomorrow is expected to bring 2 to 4 inches in the mountains and an inch in the valleys. Winds will continue to be light out of the south to the west with moderate gusts along ridgetops. Snowfall will lessen tomorrow as clouds thin. For Saturday, the general avalanche hazard above 7,500 feet will be moderate. The persistent deep slab problem continues to remain a concern. Although these slabs are becoming increasingly more stubborn, if they are triggered the consequences will be severe. These slabs will most likely be triggered by a larger load, like a snow machine, or when a thin spot in the slab is crossed. Backcountry travelers might be able to trigger an isolated pocket of wind slab on leeward slopes above 9,000 feet. Mostly stable snow exists below 7,500 feet.
