Regions
Banff Yoho Kootenay.
Watch for sudden intense solar heating. Also, the windslabs will continue to build and are likely to remain touchy to human triggering for a while. Avoid large open avalanche slopes and thin or unsupported slopes until the snowpack settles.
Weather Forecast
Warmer temps on Saturday with a little sun and snow. Then cooler again with ongoing snow, wind and sun.
Snowpack Summary
Two smaller, recent storms have left 20-50 cm of snow poorly bonded to the old crusts below. Recent moderate S-SW winds with strong gusts have formed slabs in lee areas. A firm upper snow pack sits over a weak mid-pack of facets & depth hoar. In thin snowpack areas tests results are typically collapses near the ground.
Avalanche Summary
Numerous avalanches to size 2.5 occurred Thursday morning after the passing of the storm. Most appeared to be windslabs in lee or cross-loaded areas.
Confidence
Timing or intensity of solar radiation is uncertain
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.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.