Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain.

Tuesday night: Cloudy with a storm pulse bringing 10-20 cm of new snow. Light to moderate southwest winds. 

Wednesday: Cloudy with another round of snowfall in the afternoon bringing about 5 cm of new snow, increasing overnight. Light southwest winds. Treeline high temperatures around -2 with freezing levels to 1300 metres.

Thursday: Cloudy with light flurries bringing about 5 cm of new snow and 2-day totals to 15-20 cm. Light southwest winds shifting northwest by evening. Treeline high temperatures around -3 with freezing levels to 1300 metres.

Friday: A mix of sun and cloud. Light northwest winds. Treeline high temperatures around -4 with freezing levels to 1100 metres.

On Sunday and Monday, several small skier triggered wind slabs and loose dry avalanches were reported across the region. Another very large avalanche crossed the Trans-Canada highway on Tuesday in Glacier National Park. Details remain limited but it very likely involved one of the persistent weak layers noted in our snowpack discussion.

On Saturday, isolated size 1.5 to 2.5 natural and skier triggered windslab avalanches were reported around treeline on various aspects across the region.

The persistent early December crust/facet layer has recently been active in this region. A very large storm slab avalanche (size 3) ran naturally in Mount Revelstoke National Park on Friday afternoon. Up to 3 m of snow buried the highway. This avalanche path rarely affects the road (only once every 5 or 10 years). The avalanche appears to have been caused by a storm slab that stepped down to a deeper, persistent layer. Concern for persistent slab activity like this is increasing with new snow, wind, and warming in the forecast.

15-25 cm of new is expected in the region by end of day Wednesday. This is expected to form a new storm slab problem above the mix of settling storm snow and windslabs we have in the upper snowpack after several days of consistent snowfall and southwest wind.

Our new snow and 50-90 cm of recent storm snow will be settling on top of weak, faceted snow that formed during the recent cold snap. As new snow accumulates and temperatures rise, the upper metre of the snowpack may become increasingly upside-down and more likely to avalanche. 

We're actively monitoring the early December crust. In shallow spots it's down 90 cm while in wind-loaded terrain features it can be found as deep as 200 cm below the surface. It consists of faceted grains above a bulletproof crust formed by the Atmospheric Rivers of early December. There has been avalanche activity on this crust over the weekend. Larger avalanches in surface layers as well as natural cornice falls may have potential to step down to this layer in the coming days.

• Storm slabs in motion may step down to deeper layers resulting in large avalanches.
• The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
• The likelihood of deep persistent slab avalanches will increase with each day of warm weather.