Continued loading from snow and wind Friday night through Saturday will keep the avalanche danger at HIGH.
A weak layer that formed as a crust in mid-November persists in the region. This layer may wake as rapid loading from new snow, wind, or smaller storm slab avalanches stresses deeper instabilities, resulting in larger and more destructive avalanches.
Touchy storm slabs will build through Friday night and Saturday due to heavy loading from snowfall, wind and warm tempertures.
Expect to see loose wet avalanches in steep terrain at lower elevations due to rain.
Friday Night: Snow, accumulation 15-25 cm. Alpine temperature -3 C. Moderate to strong southwest wind. Freezing level 1600 m.
Saturday: Snow, accumulation 15-30 cm. Alpine temperature -2 C. moderate to strong southwest wind. Freezing level 1700 m.
Sunday: Flurries, 5-10 cm. Alpine temperature -3 C. Moderate southwest wind. Freezing level 1000 m.
Monday: Mix of sun and cloud. Alpine temperature -4 C. light southwest wind. Freezing level 1000 m.
Expect a natural avalanche cycle to be ongoing through Saturday as slabs build due to heavy loading from snowfall, wind and warm temperatures. On Friday there were reports of widespread avalanche activity in the recent storm snow.
On Wednesday, two large natural avalanches in the Morrissey area were reported to have failed on a crust from mid-November. A cornice failure triggered a size 2.5 avalanche, and one size 2 slab avalanche failed naturally, both avalanches had crown depths 70-100 cm, were on east-northeast aspects, and suspected to have been triggered by strong winds.
Snowfall at upper elevations has covered a previously variable and wind-affected surface and is expected to build and develop reactive storm slabs. Expect the surface snow at lower elevations to be moist due to rain.
Crust layers from November and October can be found 40-100 cm below the surface. These layers produced large avalanches with explosive triggers around Dec 13-14, but since then have appeared to gain strength, but may become overloaded with incoming snow.
Snowpack depths range between 60-130 cm at higher elevations and taper rapidly below treeline.
