Avalanche Forecast

Thursday night: Cloudy with flurries bringing 10-15 cm of new snow. Moderate to strong west or southwest winds.

Friday: Cloudy with continuing isolated flurries bringing a trace of new snow. Light to moderate northwest winds. Alpine high temperatures around -7.

Saturday: Cloudy with scattered flurries bringing 5-10 cm of new snow, continuing overnight. Light to moderate south winds, becoming strong at ridgetop. Alpine high temperatures around -4.

Sunday: Cloudy with isolated flurries and a trace of new snow. Light southeast winds. Alpine high temperatures around -4 with freezing levels rising to 1300 metres.

Reports from Monday through Wednesday have shown more observations of the widespread large to very large (size 2-3) natural avalanches that have run recently, along with numerous (but diminishing) new explosives-triggered size 2-3 persistent slab releases, targeted in the Whistler area. 

Many more size 2-3 avalanches were triggered by explosives and by skiers on Saturday and Sunday. 

Many of the avalanches mentioned above either failed on the mid-November weak layer described in our Snowpack Summary or stepped down to it. Many of the larger examples scoured the lower snowpack away to reveal ground. Some of the avalanches were remotely triggered. See here for some photos of one of them.

Human-triggering of large avalanches remains a very real possibility at higher elevations. Very cautious route-finding and conservative decision making is currently required for safe travel in higher elevation avalanche terrain.

Snow surfaces across the region are a mix between newly wind-affected surfaces at exposed higher elevations and large new surface hoar in more sheltered areas. Below the surface, the upper snowpack consists of around 70 to 120 cm of snow from the storm at the end of last week. 

This storm snow overlies a variable weak layer of surface hoar and rime crust as well as a deeper (100-200 cm) weak layer of sugary faceted grains and hard melt-freeze crust buried in mid-November. 

Both of these persistent weak layers produced many large and destructive avalanches during and in the days after the storm, often with light triggers and even remote triggers. Avalanche activity on these layers has been on a downward trend, but our fundamentally unstable snowpack structure remains a serious concern in the region. It is atypical for the region and is expected to persist for some time. 

Managing your risk through conservative terrain choices along with selective avoidance of high-consequence avalanche terrain is strongly advised until the snowpack gains strength.

• Persistent slabs have potential to pull back to lower angle terrain.
• Make conservative terrain choices and avoid overhead hazard.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.