Regions
Banff Yoho Kootenay.
Natural activity is starting to taper, but given the historic nature of the last cycle, forecasters have no confidence in the current snowpack. Any slope that hasn't slid is suspect!
Weather Forecast
Southwest flow continues with flurries expected on Friday night, possible accumulations of 5-8 cm by Saturday. The temperatures will fall overnight Thursday, but expect freezing levels to reach about 1600 meters and treeline temperature from -5 to -8. Winds will remain moderate from the southwest.
Snowpack Summary
100cm of dense, rounded snow comprises the upper half of the snowpack and sits on a very weak base of depth hoar. This unstable structure produces consistent, sudden collapse test results in the depth hoar layer approximately 60cm from ground. Two shears persist near the surface down 15 and 35cm indicating lingering instability in the storm snow.
Avalanche Summary
Although the natural activity is tapering, we are still getting reports of large avalanches daily. This morning, a size 2.5 was triggered by solar radiation on a NE aspect of Jimmy Junior near Bow Summit
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.
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.