Avalanche Forecast
Regions: Bonnington, Crawford, Grohman, Kokanee, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Retallack, Rossland, South Okanagan, St. Mary, Valhalla, Ymir.
Numerous large rider triggered avalanches have been reported in recent days.
Choose conservative terrain and avoid overhead hazards.
Confidence
High
Avalanche Summary
Numerous rider triggered storm slab avalanches up to size 2 were reported on primarily north and east aspects at treeline and above on Saturday. The Nelson area has been a hot spot for recent human triggered avalanches.
Numerous naturally triggered wet loose avalanches up to size 2 were also reported throughout the region.
Snowpack Summary
Strong solar radiation has formed a surface crust everywhere except north facing terrian at upper elevations.
30 to 50 cm of recent snow overlies a crust on all but north facing aspects at treeline and above where a weak layer of surface hoar may be present.
A persistent weak layer of facets are sitting on top of a second buried crust down 100 to 180 cm. This layer is unlikely to human trigger in areas where a thick crust below the recent snow is present. However, steep or convex terrain features with a shallow or thin to thick snowpack at treeline and above are the most likely places where it may be possible to trigger this layer with large loads.
Weather Summary
Sunday Night
Clear skies. 10 to 20 km/h northwest ridgetop wind. Treeline temperature 2° C. Freezing level 2300 m.
Monday
Sunny. 20 to 30 km/h northwest ridgetop wind. Treeline temperature 5° C. Freezing level 2600 m.
Tuesday
Sunny. 20 to 30 km/h southwest ridgetop wind. Treeline temperature 8° C. Freezing level 3000 m.
Wednesday
Mix of sun and cloud with isolated flurries, 0 to 5 cm snow. 20 to 30 km/h west ridgetop wind. Treeline temperature -2° C. Freezing level 1800 m.
Check out the Mountain Weather Forecast for additional weather information.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
- If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
- Cornice failure may trigger large avalanches.
Avalanche Problems
Storm Slabs
30 to 50 cm of recent snow has formed storm slabs that are reactive to human triggers, especially in wind affected terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2.5
Persistent Slabs
Rapid warming increases the likelihood of triggering very large avalanches on deeply buried weak layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3.5
Loose Wet
Expect the high freezing levels and sunshine to trigger wet loose avalanches on all but true north aspects in the alpine.
Aspects: North East, East, South East, South, South West, West, North West.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 1.5