Clear skies and radiational cooling resulted in a light freeze overnight, causing the wet snow avalanche hazard to decrease to Low. Above 10,000 feet where the avalanche hazard will be Moderate this morning, there remains the possibility for a person to trigger a dry snow avalanche on buried persistent weak layers. Overnight temperatures in the mountains have remained close to or above freezing and the hazard will quickly increase to Moderate this morning. As surface crusts break down and lose cohesion, it will be possible for skiers and riders to trigger small to large wet slides on steep avalanche terrain. Natural-triggered wet slides and cornice failures are also possible. Although these slides may start small, wet snow avalanches could gouge down into loose wet snow and entrain dense destructive debris. Wet snow can quickly change from stable to unstable and as this occurs, steep avalanche terrain should be avoided.
As temperatures warm into the 40s and 50s and intense solar radiation affects slopes, it will be possible for a person to trigger a wet slab avalanche up to 3 feet in depth. On slopes in direct sunlight, these slides could also occur naturally.
At the upper elevations, where snow surfaces have remained dry, skiers and riders could trigger hard slab avalanche one to two feet deep on buried near surface facets and surface hoar. Hard slabs over persistent weak layers could break high into low-angle terrain and are typically triggered once the person is on the slab. Previous tracks are NOT a sign of stability and careful snowpack evaluation is essential for assessing this problem. In some areas, the warming temperatures and direct sunlight will cause these slabs to become more sensitive to triggers throughout the day.
( Discussion is generated from the previous day's afternoon forecast. )A dry air mass and ridge of high pressure will continue to dominate the weather pattern through the weekend. A shortwave system passing across the northern Rockies may bring some high clouds to the areas tomorrow through Saturday. Overnight temperatures are expected to drop into the low 20s at the upper elevations and mid-20s in the valleys. Then as the day warms, mountain temperatures will range from the 40s to 50s and valleys will climb into the 50s to 60. Southwesterly ridgetop winds will continue to be 10 to 20 miles per hour. In all the forecast areas, the wet snow avalanche hazard will start Low and then increase as the day warms. As crusts break down and snow surfaces become wet, it will be possible for a person to trigger a wet snow avalanche on steep avalanche terrain. Depending on the duration of the overnight freeze, will determine how quickly the snowpack loses cohesion. On steep solar slopes, natural-triggered small wet loose slides will be possible as well as cornice failures. Wet snow can quickly change from stable to unstable and as this occurs, steep avalanche terrain should be avoided. In the Togwotee Pass Forecast area above 10,000 feet, the dry snow avalanche hazard will be Moderate in the morning. On some slopes, a person could trigger a large persistent slab avalanche one to two feet deep. Careful evaluation of the snowpack will be needed to assess this problem.
