Strong winds, heavy precipitation and significant warming are creating dangerous avalanche conditions at upper elevations.
A hard crust with surface hoar or facets overtop is buried 40 to 100 cm deep. Storm slabs could step down to this layer, creating larger than expected avalanches.
20 to 35 cm of new snow is expected by Tuesday afternoon. Storm slabs will be most reactive in wind-loaded areas or in areas seeing rain for the first time.
Freezing levels are expected to rise to 2000 m, bringing rain to new elevations. Wet loose avalanches will be most likely in areas where a dry snow surface is being rained on for the first time.
It's been a stormy week with a significant natural avalanche cycle occurring, up to size 3. On Sunday, there were reports of size 1.5 to 2.5 slab avalanches.
With heavy precipitation, strong winds and warming in the forecast, both natural and human-triggered avalanches will be likely in the alpine.
Strong southwesterly winds and 20 to 35 mm of precipitation is expected to accumulate overnight and through Tuesday, with freezing levels potentially reaching 2000 m. The snow surface will be wet below the rain/snow line
A hard crust with a persistent weak layer of surface hoar or facets overtop is buried 40 to 100 cm deep. Storm slabs could step down to this layer, creating large avalanches. Previous rain events may have neutralized this problem at lower elevations.
Treeline snow depths throughout the region range from 250 to 450 cm.
Monday Night
Cloudy. 5 to 15 mm of precipitation as snow or rain at treeline. 40 km/h south ridgetop wind. Treeline temperature 0 °C. Freezing level 1500 m.
Tuesday
Cloudy. 10 to 25 mm of rain at treeline. 70 km/h south ridgetop wind. Treeline temperature 1 °C. Freezing level 2000 m.
Wednesday
Cloudy. 35 to 50 mm of rain at treeline. 60 km/h south ridgetop wind. Treeline temperature 2 °C. Freezing level 1600 m.
Thursday
Mostly cloudy. 10 to 25 mm of rain at treeline. 40 km/h southwest ridgetop wind. Treeline temperature 2 °C. Freezing level 1600 m.
More details can be found in the Mountain Weather Forecast.
