Avalanche conditions remain dangerous. Above 8000 feet, the snowpack is underlain by persistent weak snow layers that were covered in late November. Skiers or riders venturing into avalanche terrain could trigger large avalanches. These slides could occur even after a slope has been tracked and some potential remains for failure to occur remotely, as a group approaches terrain from above or below a slope. It is crucial to understand if slopes are underlain by the weak basal layers. This can be done quickly by digging to the ground. Be careful not to trust improving snow test scores or observations of less collapse in terrain where the weak snow is present. Avalanches below 8000 feet are not likely today.
Dangerous slab avalanches 2 to 4 feet in depth can be easily triggered by the weight of a single person. These slabs lie over weak basal facets and are most likely to be found on west to north to east facing slopes from 8000-9000 feet and all aspects at higher elevations.
( Discussion is generated from the previous day's afternoon forecast. )A weak winter storm will arrive on Thursday. Light snowfall is expected to develop in the mountains by afternoon as the flow veers to the west and brings limited moisture to the Teton Range and the southern areas of Yellowstone National Park. Accumulations of 2 to 4 inches are possible by Friday morning. Daytime highs will be in the 20s. Winds will be from thee southwest at 10 to 20 miles per hour with higher gusts.At the mid and upper elevations large slab avalanches two to four feet in depth are likely to be triggered by the weight of a single person and can be triggered on slopes that have tracks. In this terrain the general avalanche hazard will be considerable. Avalanches are unlikely below an elevation of 8,000 feet where the general avalanche hazard will be low.
