Avalanche Forecast

Moderate - Uncertainty is due to how buried persistent weak layers will react with the forecast incoming weather. Uncertainty is due to the fact that deep persistent slabs are particularly difficult to forecast.

Friday night: Cloudy, 15-25 cm of snow, transitioning to rain below about 1700 meters, strong southwest winds, alpine temperatures approaching 0 C as freezing levels climb to 1800-2000 metres.

Saturday: Cloudy, 10-15 cm of snow, moderate west and northwest winds, alpine temperatures dropping to -10 C as freezing levels fall from 1700 meters to valley bottom over the day.

Sunday: Mainly cloudy with isolated flurries and a trace of new snow, light southwest winds, alpine high temperatures around -8 C.

Monday: Mostly clear, light west winds, alpine high temperatures -10 C.

Over the past 48 hours, there have been reports of large (size 2-3) natural avalanches releasing in the recent storm snow. Due to continuous stormy weather, there have been daily avalanches reported in the region. Most of these have been storm and wind slab avalanches, on all aspects, at all elevations. They have been triggered by humans, explosives, and naturally.

With continuous stormy weather over the past week, operators have reported three persistent slab avalanches that were both naturally and skier-remote triggered. These very large (size 2.5-4) avalanches were breaking 100-200 cm deep across a variety of aspects above 1900 m. These avalanches indicate that a deeper instability may become reactive with additional loading. Touchy storm slab avalanches or cornice fall have the potential to step-down to this layer.

20-35 cm of snow fell at higher elevations on Friday. By Saturday afternoon, an additional 20-35 cm is forecast to accumulate. Forecast strong winds and warm temperatures will speed up slab formation as new snow accumulates as well as contribute to rapid cornice growth. A large, natural avalanche cycle is expected. Rain is forecast to saturate snow surfaces up to 1700 m overnight, triggering wet loose avalanches. The hazard from wet loose avalanches will decrease as temperatures cool throughout the day on Saturday. 

The mid and lower snowpack are generally well settled and strong, however there is a weak layer of surface hoar currently buried 70 to 130 cm deep. This layer has recently shown signs of instability in the region. New snow, rain, and warming will collectively add considerable strain to this weak layer. The potential for this persistent slab problem to fail naturally and produce large, destructive avalanches will increase during the storm.

• Avoid exposure to overhead avalanche terrain during periods of heavy loading from new snow, wind or rain.
• Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
• If triggered, storm slabs in-motion may step down to deeper layers and result in very large avalanches.