Avalanche Forecast
Regions: Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Jasper, Maligne, Marmot, Miette Lake, Pyramid.
The snowpack will take time to adjust to the new load.Human-triggered avalanches are still likely. Considerable rating means DANGEROUS avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making is essential.
Confidence
Moderate
Avalanche Summary
A road patrol and flight over the Icefields Parkway corridor revealed widespread natural avalanche activity during the storm. Large slab avalanches, up to size 3.5, consisted of a mix of storm slab and persistent slab, with occasional step-downs to deeper instabilities. Avalanche control using explosives triggered large storm and persistent slabs with wide propagation. Some avalanche debris reached as far as the road.
Snowpack Summary
Up to 60 cm of new snow fell over the weekend. Below this fresh snow, the snowpack is complex, with multiple crusts and facet layers creating persistent weak layers. The bottom of the snowpack consists primarily of weak facets and depth hoar.
Weather Summary
Tuesday:Cloudy with sunny periods and isolated flurries. Precipitation: Trace. Alpine temperature: High -8 °C. Ridge wind southwest: 15-30 km/h. Freezing level at valley bottom.
Wednesday
Flurries. Accumulation: 6 cm. Alpine temperature: Low -8 °C, High -4 °C. Ridge wind southwest: 15 km/h gusting to 50 km/h. Freezing level: 1700 metres.
Terrain and Travel Advice
- Use conservative route selection. Choose simple, low angle terrain with no overhead hazard.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Loose avalanches may step down to deeper layers, resulting in larger avalanches.
- Avoid exposure to overhead avalanche terrain; avalanches may run surprisingly far.
Avalanche Problems
Persistent Slabs
This avalanche problem is associated with a weak facet and crust layer, buried at the end of January, down approximately 70cm in sheltered areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 2 - 3.5
Storm Slabs
Storm slabs have the potential to trigger deeper instabilities.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1.5 - 3
Deep Persistent Slabs
Well developed facets and depth hoar at the bottom of the snow pack are still producing large avalanches in our region. Several large natural deep persistent slab avalanches released during or immediately after the storm.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2.5 - 4