Regions
Banff Yoho Kootenay.
We are in the textbook "straw that broke the camel's back" situation as the new snow, wind and facets are all adding up. The loose snow avalanches are serious, and people are going for rides. Not large avalanches, but they can run far and have power.
Weather Forecast
Continued light snowfall for the next 24 hours, with another 2-4 cm expected and temperatures ranging from -5 to -15. Moderate (40+ km/hr) westerly winds at higher elevations.
Snowpack Summary
15-20cm of recent storm snow from the past week has been blown into windslabs in high alpine areas; expect isolated soft slabs up to 40cm deep in loaded areas. Meanwhile, the overall snowpack continues to gradually become weaker from the facetting process, and in some areas the upper snowpack is comprised entirely of facets with no cohesion.
Avalanche Summary
Observed a size 2 natural avalanche that ran 800 meters on Mt. Fairview above Lake Louise today. Additionally, a party of skiers in the Lake Louise backcountry triggered a loose dry avalanche that was large enough the bury their equipment and necessitate a backcountry evacuation since they lost their gear.
Problems
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.