Avalanche Forecast
Regions: Bonnington, Crawford, Grohman, Kokanee, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Rossland, St. Mary, Ymir.
Variable freezing levels keep the upper snowpack moist; periods of sun may break down the surface crust.
Back off steep slopes if you find moist surface snow and no supportive crust.
Confidence
Moderate
Avalanche Summary
No new avalanche activity reported.
Looking forward, variable depths of storm snow may be triggered with rising freezing levels and even short windows of solar input.
A widespread large natural avalanche occurred over the past week. While activity peaked on Wednesday, human triggering is possible where there is no thick melt-freeze crust.
Read the Forecaster Blog for an opportunity to reflect on this week's widespread avalanche activity.
Snowpack Summary
New snow has buried a melt-freeze crust of variable thickness that increases in supportiveness as you gain elevation. Below this crust, snow remains moist in the upper snowpack.
Weak layers in the middle and lower snowpack remain a concern for human-triggering where a hard melt-freeze crust has not yet formed or breaks down during periods of sun and rising freezing levels.
Weather Summary
Saturday Night
Clear. 15 to 20 km/h southeast ridgetop wind. Treeline temperature -3 °C.
Sunday
Mainly clear. 20 to 30 km/h southeast ridgetop wind. Treeline temperature 0 °C. Freezing level 2000 m.
Monday
Cloudy. Flurries, 8 to 12 cm. 20 to 30 km/h northwest wind. Treeline temperature 0 °C. Freezing level 1500 m.
Tuesday
Cloudy, isolated flurries, 2 to 3 cm.15 to 20 km/h northwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1700 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- A moist or wet snow surface, pinwheeling, and natural avalanches are all indicators of a weakening snowpack.
Avalanche Problems
Storm Slabs
Storm slabs are possible where 20 cm of new snow has accumulated over a melt-freeze crust and may be initiated with rising freezing levels and periods of sun. Wet loose avalanches are likely on south-facing terrain with less than 20 cm.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
Several persistent weak layers exist in the upper meter of the snowpack. Where these layers remain intact and there is no thick melt-freeze crust human-triggering remains possible.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Unlikely
Expected Size: 2.5 - 3.5