Avalanche Forecast
Issued: Mar 6th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
Mark Herbison,
Parks Canada
Cornices have grown with recent snow and winds, limit your exposure time to overhead hazards.
Great snow quality in sheltered locations!
Summary
Weather Forecast
Has anyone seen the sun recently?... The snow fall continues, with accumulations ranging from 10-15cm by Saturday evening. The winds will be moderate from the South and the temps will range from -5 to -15. Cooler temps, moderate winds and clearing skies for Sunday into Monday.
Snowpack Summary
50-70 cm has fallen in the past week with strong Westerly winds. Expect to find wind slabs in lee areas and exposed terrain features. The recent snow is piling up and buries sun crust on steep solar aspects and the Feb 1 crust in isolated areas up to 1900m. In thin snow pack areas a dense mid-pack sits over a weak, faceted base.
Avalanche Summary
Reports of two deep persistent slab avalanches on Thursday in the alpine from South to East aspects; a sz 3 triggered by cornice fall and a sz 2.5 from explosive avalanche control.
Several natural storm slabs up to sz 2.5 observed along highway 93S Wednesday where intense wind loading was occurring.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Saturday
Problems
Storm Slabs
Expect to find wind & storm slab formation on lee aspects and open areas from the alpine to below tree line. Loose dry sluffing from steep terrain is also a concern, especially in gulleys, terrain traps and above cliffs with ongoing wind & snowfall.
- Steep unsupported terrain and slope convexities are the likely locations to awaken the storm slab.
- Watch for fresh wind slabs on exposed lee slopes and open areas at all elevations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Avalanche activity on the basal facets has slowed down but the weakness in the snowpack remains a concern. These are hard to predict, but are most likely in areas with a thin snowpack (<130cm) where the basal facets and depth hoar are prominent.
- Use caution in thin snowpack areas.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 7th, 2020 4:00PM
