Avalanche Forecast
Regions: Bonnington, Crawford, Grohman, Kokanee, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Retallack, Rossland, St. Mary, Valhalla, Ymir.
Danger is gradually decreasing with cooling temperatures, but there is enough uncertainty in the snowpack to warrant a conservative approach to avalanche terrain.
Confidence
Moderate
Avalanche Summary
Rain and warming caused a natural avalanche cycle earlier this week that included persistent slab, wet slab, and wet loose avalanches ranging from size 1 to 2.5. Activity slowed down on Wednesday with mostly small wet loose avalanches reported. The cooling trend will reduce the likelihood of avalanches, with some uncertainty about whether persistent slab avalanches are still possible.
Snowpack Summary
Surface conditions are gradually changing. A cooling trend will form a breakable crust at treeline and alpine elevations, while moist snow will remain at lower elevations. Light amounts of dry snow will accumulate over the next few days.
The recent heatwave increased the reactivity of a 30 to 60 cm deep facet and surface hoar layer, as well as a 80 to 100 cm deep facet layer above a crust. The cooling trend will likely strengthen these layers, but there is some uncertainty about how quickly this will occur and whether there will still be some isolated areas of concern.
Weather Summary
Thursday Night
Cloudy with up to 5 cm of snow above 1800 m in the Monashees and a trace in the Selkirks and Purcells, alpine wind south 20 km/h, treeline temperature around 0 °C with freezing level gradually dropping.
Friday
Cloudy with up to 5 cm of snow above 1500 m in the Selkirks (less in the Monashees and Purcells), alpine wind north 20 km/h, treeline temperature around -2 °C with freezing level gradually dropping to 1700 m.
Saturday
Mostly cloudy with 1 to 3 cm of snow in the Monashees and Selkirks and 5 to 10 cm in the Purcells, alpine wind northeast 30 km/h, treeline temperature -3 °C.
Sunday
Cloudy with 5 to 10 cm of snow, alpine wind southeast 15 km/h, treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Keep in mind that human triggering potential persists as natural avalanching tapers off.
- Carefully evaluate bigger terrain features on an individual basis before committing to them.
- As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
- A crust on the surface will help bind the snow together, but may make for tough travel conditions.
Avalanche Problems
Persistent Slabs
The likelihood of avalanches on buried weak layers is decreasing, but we are uncertain how quickly. High-consequence slopes should be approached with caution.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely
Expected Size: 2 - 2.5
Loose Wet
Wet loose avalances are possible at lower elevations where the surface has not frozen and rain is possible.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5