Regions
Banff Yoho Kootenay.
Although by definition the danger is low, there have been isolated skier remote avalanches in steep alpine terrain over the past several days. Conditions are good but its not open season, and our snowpack continues to weaken with the colder temps.
Weather Forecast
The benign weather pattern we are currently experiencing will persist for a few more days. Trace amounts of snow combined with a mix of sun and cloud is expected Tuesday. Wind will remain light from the W/NW. The temperature may dip down to the -20 range Tuesday evening.
Snowpack Summary
Trace amounts of new snow overnight. 5-10 cm of recent snow has been redistributed into thin wind slabs in immediate lee areas at treeline and above. The October 26th crust/facet layer is ~30 cm above ground. Snow depths range from 50-85 cm at 2000 m. In many areas the entire snowpack is faceting and becoming quite weak.
Avalanche Summary
No new natural avalanches observed today. There have been a few skier remote avalanches in the past several days, size 1.5-2, in isolated locations where a hard slab was sitting over the weak basal facets. Some small loose dry sluffs have also been reported in steep alpine terrain.
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.