Regions
Banff Yoho Kootenay.
The November 12 crust layer is losing strength, it should be carefully evaluated and consequences should be carefully considered before entering committing, or more aggressive terrain.
Weather Forecast
A short break from the extreme cold has brought a bit of precip and cloudy skies to southern areas over the weekend as the westerly flow won out for a while. Look for the north winds to return Monday dropping us even further into the deep freeze than we saw last week.
Snowpack Summary
Small wind slabs found in isolated alpine areas. 30-80 cm of settled snow over the November 12 crust. Stability tests on this crust are mixed, ranging from no results to easy results. This crust is more reactive in the Lake Louise area on southerly aspects above treeline. Rapid faceting and weakening of the snowpack with the cold temperatures.
Avalanche Summary
A few small loose dry avalanches observed in steep terrain as the surface snow facets and weakens. A few recent natural and skier triggered slab avalanches have been observed on southerly aspects in the alpine running on the November 12 crust.
Confidence
Due to the number and 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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.