Regions
Banff Yoho Kootenay.
Avoid exposure to avalanche terrain: large avalanches can reach valley bottom trails. Although activity should taper in the wake of this weekend's storm, as the sun comes out Monday it would be wise to watch what happens from a distance.
Weather Forecast
A ridge has established itself over British Columbia in the wake this weekend's storm and as this pushes into the region clearing will result, even if briefly, Sunday night. Despite a return to -10C temperatures at treeline through Monday night, expect solar inputs to be significant before freezing levels climb back up to 1800m late Tuesday.
Snowpack Summary
15 to 30cm of storm snow combined with moderate to strong S and W winds this weekend have built superficial wind and storm slabs. This new load combined with 40 to 80 cm of snow that has fallen in the last two weeks continues to overload the deep basal facet layers in all corners of the region. Rain to 2200m Saturday created moist to wet snow.
Avalanche Summary
New evidence of Natural activity has been observed today on patrols around the park and explosive control work has produced massive results in the Lake Louise and Yoho regions with impressive propagation. Large avalanches that initiate in the alpine and at treeline continue to entrain moist snow BTL attaining large destructive potential and reach.
Confidence
Timing or intensity of solar radiation is uncertain on Monday
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.