Regions
Banff Yoho Kootenay.
Some sporadic natural activity has been seen in the alpine, and human triggered avalanches are still possible. Current conditions are difficult to predict and a wide margin of safety is required.
Weather Forecast
Highs of -13C Saturday at 2000m and -16C at 3000m with light winds and only trace amounts of snow. Cooler temperatures in the -18 to -20C range for Sunday and Monday with continued light winds.
Snowpack Summary
There is 20-30 cm of low density storm snow (with very little wind effect) at treeline. Common through the area are the weak facets and depth hoar in the lower half of the snowpack, particularly at lower elevations and east of the divide. There is a thin rain-crust below the storm snow at lower elevations.
Avalanche Summary
2 size 2.5 natural avalanches were observed within the last 24 hours. Both were on E-SE aspects in the alpine on Mounts Ball and Brett and both appeared to scrub down to the ground. The trigger was unknown.
Confidence
Due to the number 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.