Regions
Banff Yoho Kootenay.
The natural avalanche cycle has abated, but human triggered avalanches are still possible. Current conditions are difficult to predict and a wide margin of safety is required.
Weather Forecast
Friday will be mostly cloudy with only isolated flurries. Daytime highs of -12 in the alpine and the freezing levels will be near valley bottom. Winds will be mostly light.
Snowpack Summary
There is 20-30 cm of low density storm snow (with very little wind effect) at treeline. Common through the area are the weak facets in the lower half of the snowpack, particularly at lower elevations and east of the divide. Surface hoar was observed on the surface on Thursday and there is a thin rain-crust below the storm snow at lower elevations
Avalanche Summary
There was good visibility today and the field team observed evidence of cycle from the past week including a number of skier triggered and natural avalanches around Lake Louise Ski Area and along the east side of the Banff Jasper Highway. No fresh avalanches reported in past 24 hours.
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.