Avalanche Forecast
Regions: Bonnington, Crawford, Grohman, Kokanee, Kootenay Boundary, Kootenay Pass, Moyie, Norns, North Okanagan, Rossland, South Okanagan, St. Mary, Valhalla, Whatshan, Ymir.
Heightened avalanche conditions remain where slabs have formed above a weak layer buried deep in the snowpack.
Evaluate slopes individually before committing to the terrain.
Confidence
High
Avalanche Summary
On Monday, a few natural and human-triggered wind slab avalanches were observed up to size 1.5 in the Okanagan. It is suspected that these avalanches failed on a weak layer of facets overlying a crust.
Through the weekend several, human-triggered wind slab avalanches up to size 2, were reported in the alpine and open treeline terrain.
Snowpack Summary
Alpine and open treeline terrain are generally wind-affected, with reactive wind slabs in some places. At the surface in most areas, surface hoar is forming in wind protected terrain. Around Nelson and in the Valhallas, small (5 mm) surface hoar (weak, feathery crystals) have been reported to be buried 15-20 cm below the snow surface.
Facets (weak, sugary crystals) are starting to form above a thick rain crust that was buried in early February. This crust is now 30 to 50 cm below the snow surface.
The mid and lower snowpack presents as settled, with snowpacks depths decreasing rapidly on terrain below 1000 m in elevation.
Weather Summary
Tuesday Night
Cloudy with 1 to 2 cm of snow. 10 to 25 km/h southwest ridgetop wind. Treeline temperature around -4 °C. Freezing level 1000 m.
Wednesday
Mostly cloudy with 1 cm of snow. 10 to 20 km/h southwest ridgetop wind. Treeline temperature around 0°C. Freezing level rises to 1600 m through the day.
Thursday
Mostly cloudy with 1 cm of snow. 10 to 20 km/h west ridgetop wind. Treeline temperature around 0°C. Freezing level at valley bottom overnight, rising to 1600 m through the day.
Friday
A mix of sun and cloud. 10 to 25 km/h southwest ridgetop wind. Treeline temperature +1°C. Freezing level rises to 1800 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Conditions may have improved, but be mindful that deep instabilities are still present.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Avalanche Problems
Persistent Slabs
Persistent slabs may be reactive to human triggering in areas, where winds have formed a slab above a layer of facets overlying a crust. Avalanches on this layer could propagate wider and run farther than expected.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2.5