Avalanche Forecast
Regions: Bonnington, Crawford, Grohman, Kokanee, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Rossland, St. Mary, Valhalla, Ymir.
Natural and human-triggered avalanches are likely with the arrival of more snow and wind on Wednesday.
Confidence
Moderate
Avalanche Summary
Several remotely triggered avalanches up to size 3 have been reported through the region since the weekend. These avalanches have occurred at various elevations and have been triggered from as far as 100 m away. It is suspected that these slides have occurred on the buried crust/facet layer. Check out this MIN report.
A natural size 3 avalanche was reported in the Nelson area, sliding on the same crust/facet layer. It occurred in alpine terrain in wind-loaded terrain.
Snowpack Summary
Approximately 30 to 50 cm of recent snow has buried a variety of layers that may prolong the bonding time. These layers include sun crusts on south-facing slopes and faceted snow or surface hoar in sheltered, north-facing terrain.
A widespread crust exists down roughly 50 to 80 cm. In many areas, small, weak faceted grains have formed just above or below this crust.
The lower snowpack is generally well-settled and strong.
Weather Summary
Tuesday Night
Mostly cloudy with 5 to 10 cm of snow. 20 to 40 km/h southwest ridgetop wind. Treeline temperature -12 °C.
Wednesday
Cloudy with 5 to 15 cm of snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 1500 m.
Thursday
Cloudy with 10 to 20 cm of snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 1500 m.
Friday
Mostly cloudy with 2 to 10 cm of snow. 20 to 40 km/h southwest wind. Treeline temperature -7 °C. Freezing level 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Make conservative terrain choices and avoid overhead hazard.
- Remote triggering is a concern, watch out for adjacent and overhead slopes.
- Storm slab size and sensitivity to triggering will likely increase through the day.
Avalanche Problems
Storm Slabs
New snow continues to accumulate atop various potential weak layers. Slabs are likely larger and more reactive in wind-loaded terrain features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2.5
Persistent Slabs
A widespread crust exists down roughly 40 to 80 cm. This is a particular concern in areas where weak faceted grains have formed above or below the crust.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 2 - 3.5