A forecasted storm will bring clouds and isolated flurries tomorrow. Significant snowfall accumulation is expected to begin on Sunday.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
FRIDAY NIGHT: Cloudy with isolated flurries / Alpine temperature: Low -3C / Light to south ridge wind / Freezing level valley bottomSATURDAY: Cloudy with isolated flurries / Accumulation: trace to 5cm / Alpine temperature: High -1C / Light south ridge wind / Freezing level 1200mSUNDAY: Snow / Accumulation: 40-65cm / Alpine temperature: High 0C / Moderate south ridge wind / Freezing level 1400mMONDAY: Cloudy with isolated / Accumulation: trace to 5cm / Alpine temperature: High -3C / Light southwest ridge wind with moderate gusts / Freezing levels dropping to 1100m
Avalanche Summary
Around the Whistler area, recent reverse-loading winds have created small (size 1) wind slabs in alpine lee features which are reactive to skier traffic. On steep sun exposed features in the alpine, solar warming has produced small (size 1) loose snow avalanches over the past few days.
Snowpack Summary
Days of cool, clear weather have been growing a widespread new layer of feathery surface hoar crystals on the snow surface. Recent sunshine has likely replaced this surface hoar with a new sun crust on steeper sun exposed aspects just as strong upper elevation winds scoured it from many alpine slopes.Below the surface, the recent cold has also been transforming last week's storm snow into a layer of faceted (sugary) snow. This layer of faceting storm snow increases in depth from about 20 cm at 1800-2000 m where it sits above a strong rain crust, to roughly 20-30 cm in the alpine above 2000 m, where the crust is not present. Here, depending on exposure to recent outflow winds, the storm snow either shows good signs of bonding well to our well-settled mid snowpack or has been blown away entirely.Above 2000 m, about 100-200 cm of snow now sits on the early November melt-freeze crust. This crust may be layered with weak faceted crystals in places where it lies close to the ground. This is most likely to cause problems in glaciated terrain or on smoother, high elevation slopes where the summer snow did not melt out.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.