Where dry snow exists in the alpine, watch for reactive wind slab in leeward terrain features.
A surface crust will create challenging travel conditions.
Changing winds may have formed wind slabs on all alpine aspects. Watch for stiff, smooth-looking snow and signs of instability such as cracking or whumpfing beneath your feet.
On Wednesday, reports from the region saw natural storm slab avalanches up to (size 2.5), a few cornice falls that triggered persistent slabs up to (size 3) from the slopes below.
With a cooling and drying trend on Friday, we expect avalanche activity to taper significantly until warmer weather arrives for the weekend.
A 1–3 cm thick melt-freeze surface crust will likely be present on all aspects up to 2200 m, becoming thicker and more supportive at lower elevations below 1800 m. When the sun comes out, steep sun-exposed slopes may soften. In the alpine, where dry snow persists, expect isolated pockets of wind slab and wind-affected snow surfaces. Large, overhanging cornices linger.
The prominent mid-December facet/crust layer is buried over 1 m deep and extends up to 2200 m. Triggering the crust is considered unlikely, except with large loads or in thin snowpack areas.
Thursday Night
Clear skies. 20 km/h northwest ridgetop wind. Treeline temperature -5 °C. Freezing level valley bottom.
Friday
Mix of sun and cloud. 20 km/h northwest ridgetop wind. Treeline temperature -3 °C. Freezing level valley bottom.
Saturday
Mix of sun and cloud. 20 km/h west ridgetop wind. Treeline temperature 0 °C. Alpine temperature 2 °C. Freezing level 1000 m. Strong alpine temperature inversion.
Sunday
Sunny. 20 km/h west ridgetop wind. Treeline temperature -2 °C. Alpine temperature 0 °C. Freezing level 1000 m.
More details can be found in the Mountain Weather Forecast.
