For more than a week, daily snowfall accompanied by strong winds has loaded slopes and formed wind slabs over a variety of surfaces. Above 9,000 feet, it is possible for backcountry travelers to trigger slab avalanches up to 2.5 feet in depth on avalanche-prone slopes. These slabs have been formed by the week’s weather events and could fail on a variety of layers from old buried surfaces to density breaks within the more recent snow. Backcountry travelers should use careful assessment when traveling through steep wind loaded terrain. Between 9,000 feet to 8,000 feet, avalanches will be possible to trigger on steep isolated wind-loaded features and avalanches are unlikely in the low elevations. We are sad to say that an initial report has come in about an avalanche yesterday in the Big Hole Mountains, which resulted in two fatalities. Our deepest condolences go out to the family and friends of those involved. More information will be provided as it becomes available.
Yesterday, strong southwest to northwesterly winds continued to build wind slabs at the upper elevations. These slabs will be most sensitive in steep upper elevation terrain and have the potential to step down to more deeply buried weak layers within the snowpack and be up to 2.5 feet in depth. Evaluate terrain and signs of wind loading carefully when traveling the higher elevations today.
( Discussion is generated from the previous day's afternoon forecast. )As the much-wanted unsettled weather exits the region, drier conditions are expected to arrive with little to no snowfall forecasted for tomorrow. Overnight temperatures will drop below zero and then warm into the teens in the mountains and twenties in the valleys. Moderate northwesterly winds will back to the west tomorrow and continue to be at 15 to 25 miles per hour. Tomorrow’s cold and dry weather is expected to decrease the avalanche hazard to Moderate above 8,500 feet, and below that elevation, it will continue to be Low. It is possible for backcountry travelers to trigger slab avalanches up to three feet in depth on avalanche-prone slopes at the upper elevations. These slabs have been formed by the week’s weather events and could fail on a variety of layers from old buried surfaces to density breaks within the more recent snow. Backcountry travelers should use careful assessment when traveling through steep wind loaded terrain.
