Variable amounts of new snow are expected across the region, mostly at treeline and alpine elevations. Treat the hazard as higher if local snow amounts are substantially more than forecasted.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
THURSDAY: Cloudy with light snowfall, accumulation 5 to 15 cm, light northwesterly winds, alpine temperature -1 C, freezing level 1400 m.FRIDAY: Cloudy with light snowfall, accumulation 1 to 3 cm, light southwesterly winds, alpine temperature 0 C, freezing level 1400 m.SATURDAY: Cloudy with light snowfall, accumulation 5 to 10 cm, light to moderate northeasterly winds, alpine temperature -1 C, freezing level 1200 m.
Avalanche Summary
Widespread loose wet avalanche activity to size 1.5 was observed on southerly slopes on Tuesday. Loose wet avalanche activity is expected to reduce with the cooling temperatures.
Snowpack Summary
New snow will fall on a melt-freeze crust produced with the recent warm air temperatures, sun, and rain. On shady aspects at high elevations, new snow may fall on lingering wind slabs in lee features and loose dry snow in sheltered features.Deeper in the snowpack, the mid-December and late November weak layers are composed of crusts and sugary facets, which are down 200-300 cm. These layers have been dormant but may be awoken by a large trigger, such as a cornice fall.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.