Regions
Banff Yoho Kootenay.
Basal instabilities can result in large avalanches with high consequences. Thinner snowpack areas will be more touchy and prone to avalanche. Make conservative choices.
Weather Forecast
10 to 15 cm is expected in the alpine by Saturday night. SW winds are expected to be in the moderate range for the same period. Windslabs would be expected to develop.
Snowpack Summary
40 to 60cm of settled snow sits on large facetted grains of varying strength. Treeline snow depths generally range from 100 to 150 cm. The facets in the lower portion of the snowpack are failing in tests often in the moderate range. Alpine, and open treeline areas can have great variability in snow depth and layering due to local winds.
Avalanche Summary
No avalanches observed or reported today.
Confidence
Intensity of incoming weather systems is uncertain
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.