Regions
Banff Yoho Kootenay.
The snowpack is complex this year with multiple weak layers. The best way to manage this is to stick to conservative terrain and minimize your overhead hazard.
Weather Forecast
A series of small storms are moving in off the coast. Expect light to moderate snow with 5- 10 cm per day over the next three days. The most snow will fall to the north and west along the divide with up to 25 cm by end of Thursday. Temperatures will be cool with -10 to -12'C at upper elevations. 3000m winds will generally be moderate to strong SW
Snowpack Summary
Windslabs exist in the alpine. In sheltered areas, 20-30cm of new snow overlies the Jan 16 (the first of 3 weak layers). Below this are the Jan 6 (down 40-50) and Dec 15 (down 60-80). Each of these layers is a mix of sun crust, surface hoar and facets depending on aspect and elevation. Below treeline, the snowpack is facetted with little structure.
Avalanche Summary
No new avalanches were reported or observed today. Yesterday, a couple size 2 natural avalanches were observed in the Sunshine Backcountry. Both were likely cornice triggered out of wind loaded alpine terrain.
Confidence
Intensity of incoming weather systems is uncertain
Problems
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.