Yesterday, a snowmobiler was caught and killed in a large avalanche in the Squaw Creek Drainage located in the Grey’s River area southeast of Alpine. The Bridger-Teton Avalanche Center will be conducting an investigation of this accident. Also over the past week, there have been many large human-triggered and natural avalanches in the forecast areas. Backcountry travelers could encounter these dangerous avalanche conditions today, and when traveling in avalanche-prone terrain are likely to trigger large to very large avalanches. Expert snowpack and terrain analysis skills are essential for safe travel in avalanche terrain, and if triggered slides could run long distances.
Large to very slab avalanches could be easily triggered by a person or by a smaller wind slab on a variety of aspects. These slabs could be three to six feet deep.
In steep terrain above 8,000 feet, west to southwest to northwest winds have formed wind slabs on leeward aspects. These slabs could be human-triggered and are likely to be 1 to 3 feet deep. The initiation of surface slabs could step down to weak layers deeper in the snowpack and become large to very large persistent slab avalanches.
( Discussion is generated from the previous day's afternoon forecast. )Overnight, there is a chance for bands of snow in an unsettled northwest flow to cross over Western Wyoming. Then by morning, a transitory ridge is expected to build over the region and bring mostly dry weather for up to twenty-four hours. Mountain temperatures are expected to be cold in the single digits and then warm into the mid to upper teens. Winds will back to the west at fifteen to twenty-five miles per hour. After the past week's significant loading event, it will take time for the snowpack to adjust and become more stable. In the Grey’s River and Togwotee Pass forecast areas, dangerous avalanche conditions remain a concern, and the avalanche hazard is expected to be Considerable tomorrow. Riders and skiers could trigger unsurvivable slab avalanches 3 to 6 feet in-depth as well as smaller wind slab avalanches and dangerous sluffs on steep avalanche terrain. Keep in mind, triggering a smaller slab could initiate the failure of a very large avalanche. In the Teton forecast area, where the snowpack is less unstable than the other forecast areas, there is the potential for backcountry travelers to trigger slab avalanches one to four feet in-depth at all elevations, and the hazard will remain Considerable at the upper elevations and Moderate at the mid and lower elevations. It is essential for all backcountry travelers to carefully evaluate the snowpack and choose conservative terrain as conditions adjust.
