Regions
Banff Yoho Kootenay.
The hazard has improved, but it will still wise to stick to conservative choices for sometime given the weak snowpack structure.
Weather Forecast
There is no new snow in the near-term weather forecast, as a ridge of high pressure remains stationary over the central rockies. Some cloud cover may appear, but no precipitation is expected and temperatures on Friday will range from -5 to -10 and light to moderate W winds.
Snowpack Summary
In many areas, the surface snow remain unaffected by wind and overlies a generally weak and facetted mid-pack and base - particularly in the Lake Louise area and on the east side of Hwy 93 north. Closer to the divide, the deeper snowpacks are stronger and more supportive. Surface hoar up to 10mm continues to grow on the snow surface.
Avalanche Summary
Out of 24 shots in the Kootenay highway paths only 1 size 3 was triggered from the top of Mt. Whymper sliding on a layer near ground. Only 1 natural was observed on a North aspect where a cornice failure triggered a size 2 slab in the past 2 days. Despite the encouraging results, little confidence in the overall weak snowpack structure remains.
Confidence
Due to the quality of field observations
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.