Sustained westerly to southwesterly winds and 10 to 14 inches of new snow, since late Thursday night, have formed wind slabs on leeward slopes that will be easily triggered by riders and skiers today. Although these newly formed wind slabs will be the most sensitive to triggers, the main concern remains the increased load on deeply buried weak layers. In areas with poor snowpack structure, a single person or the release of a wind slab could trigger a large to very large avalanche that will be unsurvivable and run long distances into lower elevation terrain. Natural avalanches are also possible. The avalanche hazard will remain High above 8,000 feet, where slabs will be larger and more sensitive, and Considerable below that elevation. Avalanches are likely today, and travel in or below avalanche terrain is not recommended.
Very large persistent deep slab avalanches are likely to be triggered by riders or skiers who venture onto steep slopes. Natural releases are possible. These dangerous slab avalanches could be 4 to 8 feet deep. If you trigger one of these destructive slides, you will most likely not survive. Previous tracks on a slope should NOT be interpreted as a sign of stability.
Westerly to southwesterly winds have formed fresh wind slabs on leeward aspects. These surface slabs could be 1 to 4 feet deep and will become more sensitive to human triggers as the day progresses. These wind slab avalanches could step down and trigger a much larger deep persistent slab avalanche.
( Discussion is generated from the previous day's afternoon forecast. )Snowfall is expected to continue overnight with an additional 4 to 8 inches across the forecast area by morning. The heavier snowfall amounts should continue to favor the Grey’s River and Teton forecast areas. Southwesterly to westerly ridgetop winds will be 15 to 30 mph and then lessen by tomorrow afternoon. A weak northwest flow will bring mostly cloudy skies and light snowfall through tomorrow, and then dry weather is expected as a ridge builds over the region. Temperatures will be cold starting in the single digits and then warming into the low to mid-teens. Snowfall and wind continue to load the snowpack and form wind slabs on leeward slopes. Humans are likely to trigger slab avalanches up to 8 feet deep. Winds slabs at the upper elevations are expected to be sensitive and up to 3 feet deep. Triggering a smaller wind slab could step down and initiate a larger avalanche with un-survivable consequences. Depending on the intensity and duration of the storm overnight will determine the likelihood of triggering an avalanche tomorrow. At the highest elevations, the avalanche hazard is expected to be High and Considerable in areas with less snowfall and wind effect. Regardless, conditions are dangerous and travel in avalanche terrain is not recommended.
