Regions
Banff Yoho Kootenay.
Very good skiing and travel conditions are present a higher elevations, but it makes sense to stick to conservative terrain choices with minimal overhead hazard. We are still getting fairly regular reports of large natural avalanches running far.
Weather Forecast
Increasing cloudiness with freezing levels up to 1800m and slightly warmer temperatures are forecast on Monday with daytime highs at valley bottom approaching 10 degrees and lows below freezing. Expect a few cm's of new snow in the alpine with Moderate SW winds.
Snowpack Summary
10-15cm of snow sits over a solid 100cm+ slab which rests precariously over the weak basal facets at treeline and above. Tests produce consistent sudden collapse results in the facets. Some wind slabs present near alpine ridges, and sun crust on solar aspects. Below treeline a melt freeze cycle is developing, with the snowpack weakening in the PM.
Avalanche Summary
Natural activity has decreased over the last few days however avalanche reports continue to come in. A cornice triggered Na size 3 was observed on Fatigue Mountain Sunday, and reports of solar triggered avalanches up to size 3 East of our forecast area. It still appears to take only small inputs of sun, wind or precip to trigger natural events.
Confidence
Freezing levels are 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.