Recent snowfall and strong southwesterly winds have created dangerous avalanche conditions. Since the early hours on December 23, there has been 16 to 22 inches of new snow with up to 2 inches of water. This rapid loading has made it likely for human-triggered, small to large, slab avalanches on steep wind-loaded terrain and isolated terrain features at the mid and upper elevations. Natural avalanches are possible at the upper elevations. High wind speeds have probably caused snow surfaces to become stiff, and slabs could break above the trigger. Due to all the new snow, avalanche debris could entrain snow and grow in size. Today, backcountry travelers should use cautions route-finding, careful evaluation of the snowpack, and conservative decision-making. And Merry Christmas!
New snow and strong winds continue to form wind slabs on leeward slopes. High wind speeds with gusts into the upper 50s have likely formed hard slabs and transported snow into sheltered areas. These hard slabs may be too firm to ski cut and crowns could be lower in the start zones. Slabs could be up to 3 feet in depth.
The interface of the December 5th old snow layers deeper in the snowpack still remains a concern. The increased loading over these layers will add stress and the potential to trigger a deeper avalanche up to 4 feet in depth. So far, the majority of the reported activity on this layer has been below 9,000 feet.
Snowfall is expected through tomorrow night with accumulations of 8 to 16 inches in the Southwest Trails, 7 to 14 in the Tetons, and 3 to 6 on Togwotee Pass. Southwesterly ridgetop winds overnight will veer to the west tomorrow morning and are expected to be 20 to 30 miles per hour with higher gusts. Mountain temperatures will be in the teens and valleys in the twenties. At the upper elevations, the avalanche danger will remain Considerable as snowfall and steady winds continue to impact the area and create dangerous avalanche conditions. On steep wind-loaded starting zones, it will be likely for skiers and riders to trigger slab avalanches 1 to 3 feet in depth. If triggered, these slides could entrain new snow and grow in size. In isolated areas, deeper slab avalanches up to 4 feet in depth could be triggered on old faceted snow that formed earlier in the season.
