Regions
Banff Yoho Kootenay.
Anticipated snow Tuesday/Wednesday did not materialize. Next system to arrive Thurs-Friday night. Expect the danger to rise.
Weather Forecast
For Thursday, expect scattered flurries, gusty SW winds, and alpine highs around -6C. Snow to move into the region late Thursday/Friday morning with moderate to strong SW wind. The total snowfall is uncertain, but could be in the range of 15-25 cm.
Snowpack Summary
There is 15-25 cm of low density snow at tree line with a thin rain-crust below the storm snow at lower elevations. Some wind effect exists in alpine areas and it is expected to increase. Common throughout the region are the weak facets and depth hoar in the lower half of the snowpack, overlain by a 40-60 cm slab of well settled snow.
Avalanche Summary
No new avalanche activity was observed or reported on Wednesday.
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.