Although the natural avalanche cycle may be over, rider-triggered avalanches remain likely, especially where a supportive crust has not yet formed on the surface.
Recent snow, rain, and winds have created widespread storm slabs. Cooling temperatures on Thursday should help these slabs gradually stabilize.
Numerous storm slab avalanches, ranging from size 1 to 3, were reported on Tuesday. These occurred on all aspects and elevation bands, and were primarily triggered naturally or by explosives. A few of these avalanches stepped down to a layer of surface hoar described in the snowpack summary.
While natural avalanche activity is expected to decrease by Thursday, rider-triggered avalanches will remain likely.
Warm, wet conditions on Wednesday night will create heavy, moist snow on the surface or a crust, depending on elevation and location. Another thin melt-freeze crust is likely just beneath the surface within recent storm snow.
A mid-November crust with facets or surface hoar above is buried 50 to 100 cm deep.
The lower snowpack is generally well settled and bonded, except in thin, rocky areas where weak basal facets may have formed.
Snowpack depth at treeline is roughly 90 to 160 cm, but tapers quickly at lower elevations, meaning many below-treeline slopes do not have the snow coverage to avalanche.
Wednesday Night
Cloudy. 5 to 15 mm of a mix of snow and rain at treeline. 60 km/h west ridgetop wind. Treeline temperature 1 °C. Freezing level 2100 m.
Thursday
Mix of sun and clouds. 40 km/h west ridgetop wind, decreasing through the day. Treeline temperature -3 °C. Freezing level 1600 m.
Friday
Mostly cloudy. 1 to 2 cm of snow. 40 km/h west ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 m, and rising through the day.
Saturday
Mostly cloudy. 1 to 2 mm of precipitation as snow or rain at treeline. 40 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 2000 m.
More details can be found in the Mountain Weather Forecast.
