Avalanche Forecast
Regions: Bonnington, Crawford, Grohman, Kokanee, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Retallack, Rossland, St. Mary, Valhalla, Whatshan, Ymir.
15 to 25 cm of recent snow and southwest wind have formed fresh storm slabs.
Expect strong solar radiation to increase the likelihood of triggering slabs.
Confidence
Moderate
Avalanche Summary
On Thursday, numerous skier triggered storm slabs up to size 1.5 and one size 2 persistent slab were reported. They occurred primarily on northerly and easterly aspects. Here's one example.
Additionally, a naturally triggered size 3 persistent slab was reported on northeast aspect in the alpine. It was likely triggered by either rapid loading or a cornice fall.
Snowpack Summary
15 to 25 cm of recent snow and southwest wind have formed fresh storm slabs reactive to human triggers.
Concern remains for triggering persistent slab avalanches. These layers include:
Facets/surface hoar/crust from early March buried 40-70 cm.
Facets/surface hoar/crust from mid-February buried 60-100 cm
Facets/surface hoar/crust from late January buried 100-160 cm.
The lower snowpack is well settled and strong.
Weather Summary
Friday night
Cloudy with 0 to 10 cm of snow (isolated areas could receive up to 20 cm). 10 to 20 km/h west ridgetop winds. Treeline temperature -8 °C. Freezing level valley bottom.
Saturday
Mix of sun and cloud. 10 to 20 km/h west winds. Treeline temperature -4 °C. Freezing level 1500 m.
Sunday
Mostly cloudy with 5 to 15 cm snow. 10 to 20 km/h southwest ridgetop winds. Treeline temperature -4 °C. Freezing level 1400 m.
Monday
Moslty cloudy with 0 to 5 cm of snow. 20 to 30 km/h southwest ridgetop winds. Treeline temperature 2 °C. Freezing level rapidly rising to 2200 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks, or recent avalanches.
- Use small, low consequence slopes to test the bond of the new snow.
- Be aware of the potential for larger than expected storm slabs due to buried surface hoar.
- Even brief periods of direct sun could produce natural avalanches.
Avalanche Problems
Storm Slabs
15 to 25 cm of recent snow and southwest wind have formed fresh storm slabs.
Expect strong solar radiation to increase the likelihood of triggering slabs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Persistent Slabs
Several persistent weak layers exist in the upper metre of the snowpack. Small avalanches in motion may trigger these deeper layers creating very large and destructive avalanches.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3
Loose Wet
Expect strong solar radiation to trigger small wet loose avalanches and increase the likelihood of triggering slabs.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood: Likely - Very Likely
Expected Size: 1 - 1.5