Regions
Banff Yoho Kootenay.
The snowpack is slowly strengthening; however, conservative decision making in bigger alpine terrain is still essential! We may see some snow late friday PM which would cause the danger to rise again.
Weather Forecast
Thursday and Friday look to be similar to the last few days - mild temperatures, light winds and scattered clouds. Friday afternoon, we should see increased winds from the West and 10-15 cm's overnight with freezing levels rising to ~1500m.
Snowpack Summary
The snowpack remains fundamentally weak, with a combination of windslab, surface hoar and basal facets all causing concern in different types of terrain. Snowpack tests continue to produce moderate to hard sudden results on the basal weakness/ Dec. 18th interface which has become one and the same in many areas.
Avalanche Summary
No natural avalanches observed, but forecasters on Mt. Field reported a couple large whumphs in an open area below treeline, indicating human triggering of deeper weak layers is still possible in the right terrain.
Confidence
Forecast snowfall amounts are uncertain on Saturday
Problems
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.
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.