Regions
Banff Yoho Kootenay.
The only thing certain about the snowpack right now, is how unpredictable it is.
Weather Forecast
The NW flow continues to run down through the forecast region keeping temperatures cool with bursts of snowfall and gusty winds as systems embedded in this flow pass through the area. Trace amounts of snow are expected for Sunday; then another 5 cm for Monday.
Snowpack Summary
10-20 cm of soft surface snow has formed thin windslabs in some areas, and sits on top of a shallow and weak snowpack. West of the Continental Divide the snowpack is stronger, but failures near the ground are still likely. This condition will persist until the passage of time and deeper snow can work to strengthen the lower half of the snowpack.
Avalanche Summary
There is a pattern emerging in the Lake Louise area where the snowpack is the shallowest. Steep gullies in alpine areas are producing 100cm deep avalanches to ground (up to size 2), with triggering occurring from thin spots where the snowpack is weakest. A ride in these full-depth avalanches would cause serious injury getting raked over the rocks.
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.