Strong winds may build reactive wind slabs at upper elevations, while a deeper persistent weak layer remains a concern
Start with conservative terrain and watch for signs of instability
Strong southwesterly winds on Monday may form new and reactive wind slabs at upper elevations. Older wind slabs from previous northerly winds may still be triggerable.
A crust with facets buried 50 to 170 cm produced a widespread cycle of natural and human-triggered avalanches last week. Remote triggering and step-down potential continue to be a concern with this layer.
Jan 3
Numerous natural slab avalanches up to size 2 were observed in Pine Pass out of steep south-facing alpine areas.
Jan 2
Explosive control produced a few size 1.5 slabs in steep treeline terrain.
Dec 31
A very large naturally-triggered size 3.5 avalanche failed on the persistent weak layer.
Recent snowfall has been blown into slabs in leeward alpine and treeline terrain by winds from variable directions.
A persistent weak layer formed in mid-December, consisting of a crust with weak facets, was the cause of a large natural avalanche cycle in the middle of last week. This layer is now buried 50 to 170 cm deep, depending on the aspect and wind loading.
In thin snowpack areas, faceted grains or depth hoar may exist at the base of the snowpack.
Sunday Night
Partly cloudy. 1 to 3 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -16 °C.
Monday
Mostly cloudy. 1 to 2 cm of snow. 50 km/h southwest ridgetop wind. Treeline temperature -14 °C.
Tuesday
Cloudy. 15 to 20 cm of snow. 50 km/h southwest ridgetop wind. Treeline temperature -7 °C.
Wednesday
Cloudy. 4 to 10 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -7 °C.
More details can be found in the Mountain Weather Forecast.
