Regions
Banff Yoho Kootenay.
The avalanche hazard will slowly begin to increase as the snow arrives tonight and more conservative terrain choices will be necessary over the next few days. Enjoy the new snow!
Weather Forecast
5-10cm of snow is forecast for Monday night and Tuesday with an additional 15-20cm of snow forecast for Wednesday. This will be accompanied by moderate to strong W winds and rising temperatures with freezing levels of about 1500m by Wednesday night.
Snowpack Summary
5-15 cm of facetted surface snow sits over the January 30th surface hoar layers. This facet/surface hoar combination will be one to watch as we begin to get more snow. Variable wind effect in the alpine with sun crust on steep solar aspects. The basal facet/depth hoar problem persists but is well bridged in deeper snowpack areas.
Avalanche Summary
No new avalanches have been observed or reported today.
Confidence
Forecast snowfall amounts are uncertain on Wednesday
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.