Avalanche Forecast
Regions: Bonnington, Crawford, Grohman, Kokanee, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Retallack, Rossland, South Okanagan, St. Mary, Valhalla, Ymir.
Rapidly rising freezing levels are expected to increase the likelihood of triggering large avalanches.
Choose conservative terrain and avoid overhead hazards.
Confidence
High
Avalanche Summary
Numerous rider triggered storm slab avalanches up to size 1.5 were reported on primarily northerly aspects at treeline and above on Sunday. The Nelson area has been a hot spot for recent human triggered avalanches.
Numerous naturally triggered wet loose avalanches up to size 1.5 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 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
Monday Night
Clear skies. 10 to 20 km/h west ridgetop wind. Treeline temperature 6° C. Freezing level 2700 m.
Tuesday
Sunny. 20 to 30 km/h southwest ridgetop wind. Treeline temperature 8° C. Freezing level 2800 m.
Wednesday
Mix of sun and cloud with isolated flurries, 0 to 5 cm snow. 10 to 20 km/h west ridgetop wind. Treeline temperature -1° C. Freezing level 1800 m.
Thursday
Mix of sun and cloud. 10 to 20 km/h northeast ridgetop wind. Treeline temperature -2° C. Freezing level 1700 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
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- 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
Storm slabs continue to be reactive to human triggers, especially at treeline and above. They have been failing just above a crust down 30 to 50 cm.
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: Possible
Expected Size: 2 - 3.5
Loose Wet
Expect the high freezing levels to trigger wet loose avalanches on all aspects and elevations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 1.5