Avalanche Forecast
Regions: Bonnington, Crawford, Grohman, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Rossland, Ymir.
Fresh wind slabs are forming on lee slopes and triggering persistent slabs remains possible.
Retreat to more conservative terrain if you experience signs of instability.
Confidence
Moderate
Avalanche Summary
On Friday a few naturally-triggered wind slabs were observed near Kootenay Pass from lee southerly slopes. A remotely-triggered slab was also observed there on a steep bank below treeline.
On Wednesday a rider remotely triggered a persistent slab avalanche (size 2) on an east-facing slope just above 2000 m. (See photo below)
Dry loose sluffing continues to be observed from steep terrain features.
Snowpack Summary
Exposed terrain in the alpine and treeline is variably wind-affected. Up to 10 cm of new snow is expected in some areas by the end of the day Sunday. This will add to a recent snowfall of around 5 cm, which is covering a layer of surface hoar in many areas, or a thin suncrust on steep south-facing slopes. Below that, 20 to 60 cm of faceted snow overlies a persistent weak layer from late January. This layer consists of a crust on sun-exposed slopes and surface hoar on all other aspects. Recent snowpack tests indicate that an overlying stiff and consolidated slab is generally required for it to be reactive. The remaining is generally well settled.
Weather Summary
Saturday Night
Cloudy with 2 to 5 cm of snow. 20 to 25 km/h south ridgetop wind. Treeline temperature -10 °C.
Sunday
Cloudy with 3 to 6 cm of snow. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -9 °C.
Monday
Cloudy with 0 to 3 cm of snow. 15 km/h variable ridgetop wind. Treeline temperature -8 °C.
Tuesday
Sunny. 10 to 25 km/h northwest ridgetop wind. Treeline temperature -7 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be careful as you transition into wind-affected terrain.
- Approach steep and open slopes at and below treeline cautiously, as buried surface hoar may exist.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks, or recent avalanches.
Avalanche Problems
Wind Slabs
New snow combined with moderate winds are expected to form reactive new wind slabs in lee terrain. Be careful with wind-loaded pockets, especially near ridge crests and rollovers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1.5
Persistent Slabs
A layer of surface hoar buried 20 to 60 cm has been reactive where a cohesive slab exists above it.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2