Regions
Banff Yoho Kootenay.
Great skiing can be found in wind sheltered terrain, especially below between 1750-2500 metres. (LP)
Weather Forecast
For the next few days leading into the weekend, expect seasonal temperatures (-8 to -13) and the occasional snow flurry bringing light amounts of snow. Moderate West to North West winds will add to the chill and may add to the alpine surface windslab issue.
Snowpack Summary
Variable surface wind slabs have been found in immediate lee ridge features, as well as open terrain above 2800m. In sheltered locations, very good skiing can be found from 2500m to as low as 1750m. Lower than that and things get a bit thin . A well-settled mid-pack sits atop the Nov 6 rain crust, which is starting to break down in some locations.
Avalanche Summary
A couple of cornice triggered size 1-1.5 slab avalanches, 20-40 cm thick, in the last 24 hours above the Bourgeau left ice climb (SE asp) near Sunshiine. They ran quite far for their mass, but stopped about 150 m above the climb. No other new avalanches reported today.
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.
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.