Above 7,500, skiers and riders could trigger persistent slab avalanches one to two feet deep on steep avalanche-prone terrain. These slabs may take a larger trigger or an individual crossing a thin area of the snowpack to initiate the avalanche. Since these persistent layers lie beneath a slab of snow, it may be hard to detect the hazard without assessing the snowpack structure, and old tracks should not be trusted. Below 7,500 feet, where the snowpack is thin, avalanches are unlikely except for isolated pockets on steep slopes. This type of avalanche problem is best managed by terrain assessment and safe travel techniques of only exposing one person at a time. Evaluate steep slopes carefully and anticipate the potential consequences of triggering a slab avalanche.
Since the dry period ended on December 11th, over two feet of snow containing over two inches of moisture has fallen in the Togwotee Pass forecast area. Beneath that snow lies weak faceted snow grains and crusts that form good sliding surfaces and potential failure layers within the snowpack. Be particularly wary of unsupported slopes and cliff areas.
( Discussion is generated from the previous day's afternoon forecast. )Dry weather will continue tomorrow with mostly clear skies and a valley inversion. In the mountains, temperatures are expected to start in the single digits and then warm into the twenties, while in the valleys temperatures should start below zero and then also warm into the twenties. Northwesterly winds are expected to be light at 10 to 20 miles per hour. In the Southwest Trails/Grey’s River and Teton forecast areas, the general avalanche hazard is expected to remain Considerable above 7,500 feet. In these areas, persistent slab avalanches are likely to be triggered by skiers and riders on steep avalanche-prone terrain. Buried weak layers vary in distribution and in some areas may be stubborn, but where this structure exists dangerous avalanche conditions could be encountered. These problem layers could be hard to detect without checking the snowpack structure. In the Continental Divide/Togwotee Pass forecast area, where there was less snowfall since December 11, the general avalanche hazard is expected to be Moderate. It remains possible for skiers and riders to trigger persistent slab avalanches one to two feet deep. In all the forecast areas, below 7,500 feet the general avalanche hazard is Low. At these lower elevations, there is only one to two feet of snow, which has experienced above freezing temperatures for over 24 hours, and avalanches are unlikely except for isolated pockets of deeper snowpack on steep slopes.
