High pressure with cold arctic air will dominate the area through Saturday morning. At the high elevations, backcountry riders or skiers could trigger wind slabs on a variety of aspects and still have a slight chance of triggering deep persistent slabs on certain aspects. At the mid and low elevations, avalanches are unlikely except for in small, isolated pockets in very steep terrain.
At the upper elevations soft to dense slabs could be triggered with depths to one foot in steep wind loaded terrain. Winds have varied from the southwest during recent snowfall to the northeast and are backing to the west today, therefore all aspects and specific terrain features should be evaluated.
Although unlikely, deep slabs remain a concern in avalanche prone terrain above an elevation of 9,000 feet on west through north through east aspects. The release of one of these large destructive avalanches, that could have crowns to six feet, is more likely with a large trigger, such as a snowmobile or a group of people. Previous tracks are not an indication of stability. Snowpack evaluation is essential to properly manage this concern.
The region is in store for another bitterly cold night with temperatures dropping to near negative 20 in the valleys and around negative 10 in the mountains. As cloud cover increases during the day, inverted conditions will break down, and temperatures will climb into the low teens at the higher elevations and high teens in the lower elevations. Snowfall will begin to develop Saturday evening as a strong Pacific storm system starts to impact the region. Westerly ridgetop winds will back to the southwest at 10 to 20 miles per hour.The general avalanche hazard is expected to be MODERATE throughout the three forecast areas on Saturday. Persistent deep slabs will continue to be a threat on shaded and partially shaded slopes above 9,000 feet. The persistent weaknesses near the base of the snowpack will be most easily impacted in the shallower snowpack of the Togwotee Pass forecast zone. Conversely, the deepest snowpack is found in the Tetons, and the chance of triggering one of these slides is unlikely, but the consequences would be greater. The Greys River area lies somewhere in the middle in terms of snow depth. That area also recently experienced a significant loading event, and the likelihood of triggering a deep persistent slab will remain possible. Skies and riders could also trigger recently developed wind slabs in steep, wind-loaded avalanche terrain. These slabs could be up to three feet deep in the Greys River forecast zone, and generally around a foot or less in the Teton and Togwotee Pass areas.
