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.
This avalanche problem is associated with a weak facet and crust layer, buried at the end of January, down approximately 70cm in sheltered areas.
Storm slabs have the potential to trigger deeper instabilities.
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.
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.
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.
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.
