Regions
Banff Yoho Kootenay.
Forecasters experienced a large whumph above Pika Flats in the Lake Louise back-country today. This emphasizes that there is still potential for human triggering, especially in shallow areas.
Weather Forecast
Light wind, clear skies and little to no precipitation are expected over the next couple of days. The main concern will be solar radiation on south aspects. Although the solar effect may not change the danger rating, it could induce moist avalanches on a local level.
Snowpack Summary
A well settled upper snowpack with highly variable depths sits over the ever present weak facets and depth hoar in the bottom half of the snowpack. Colder temperatures have helped the slab bridge over the weaker base. Expect to find wind slabs in lee areas in the alpine.
Avalanche Summary
No new avalanches were observed or reported today.
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.