Regions
Banff Yoho Kootenay.
The weak and facetted mid-pack that prevails in most areas warrants conservative route choices, especially in the alpine.
Weather Forecast
Wednesday will be mainly cloudy with day-time highs in the alpine around -10. Winds are forecast to be light and freezing levels will be near the surface. Little change is expected through Friday.
Snowpack Summary
20-40 cm of settled snow overrides a generally weak and facetted mid-pack and base. Closer to the divide, and in deeper snowpack areas the midpack is more supportive. Some lingering windslabs may exist in the alpine. Surface hoar (up to 10 mm) was noted in the alpine around Sunshine today.
Avalanche Summary
Avalanche control in Yoho Park on Monday produced numerous size 2 -2.5 avalanches on Mt. Dennis. One size 3 avalanche on Mt Bosworth. These were storm slabs or wind slabs that stepped down into a lower facet layer.Report of several size 2 avalanches in Bow Summit area. These were in the alpine on south /south west aspects and ran in past 72 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.