Regions
Banff Yoho Kootenay.
We have little confidence in the weak snowpack. If there is a slab overlying facets, its suspect.
Weather Forecast
Lows of -25C rising to around -12C with sunny skies and very light SW wind for Friday morning Cloud to roll in the afternoon with flurries starting in the evening. There is potential for significant snow through the weekend in some areas. Weather models are not in agreement and the brunt of the system may be to the South. Stay tunned....
Snowpack Summary
Previous strong to extreme W winds have created harder wind pressed surfaces at treeline and above. Isolated surface hoar may be found buried in sheltered locations at treeline and below. Generally the midpack is weak at TL and above, and the entire snowpack is weak BTL. Near the divide, deeper snow-packs are a bit stronger and more supportive.
Avalanche Summary
We had a small avalanche cycle this past weekend due to big winds, but as temperatures have cooled and winds abated, the activity has slowed down significantly. No new avalanches reported or observed Thursday.
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.