Regions
Banff Yoho Kootenay.
The freezing levels should lower tonight and form crusts. Pay attention to the strength of these crusts at tree line and below this weekend as the wet snow beneath has no strength. Cornices are weak and fragile on north aspects so keep an eye out.
Weather Forecast
The winds will abate as a cold front passes tonight ushering in cooler air and lower freezing levels along with some light precipitation amounts for Saturday morning. Strong westerly winds at ridgetop will continue mid Saturday through the weekend with scattered precipitation.
Snowpack Summary
Sustained moderate to strong winds aloft continued to build wind slabs and cornices at ridge top today. Moist snow to 2400 meters on polar aspects (North) and moist to ridge top on the solar slopes. Mid pack is well settled and overlies a largely weak basal depth hoar or facets.
Avalanche Summary
Several natural avalanches occurred today up to size 2.5 around the Sunshine Ski Area back country. Many loose wet avalanches with some of them triggering slab avalanches in the lower track below tree line. Suspect with today's warm temps that cornices will be very touchy.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Saturday
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.