Regions
Banff Yoho Kootenay.
Thin areas will be the most susceptible to triggering the weaker basal facets/ depth hoar. This problem is now hard to predict, and comes down to your level of comfort with the uncertainty combined with the type of terrain you choose.
Weather Forecast
Continued mild temperatures for January with highs in the -2 to -4C range at valley bottom and -8 to -10C at 3000m with West winds increasing to strong in the alpine. Only a few cm of snow is expected over the next 2 days.
Snowpack Summary
10-20cm of snow over the last few days. Thin wind slabs can be found in alpine lee areas from strong SW winds on Saturday. Of greatest concern are the weak facets and depth hoar at the base of the snowpack. In thinner snowpack areas with less than 150 cm of snow, triggering a slab on these facets is more likely.
Avalanche Summary
No new avalanches reported or observed.
Confidence
Due to the number and quality of field observations
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.