Regions
Banff Yoho Kootenay.
Reports of two skier accidental and numerous natural avalanches today to size 2 failing on the developing wind slab facet interface.
Weather Forecast
More snow is expected to fall with amounts ranging from 5-10cm in the next day. As this system moves through, moderate to strong westerly winds will continue to persist at higher elevations. Temperatures are forecasted to remain between -5 to -15 for the next few days.
Snowpack Summary
Moderate to strong winds have transported 5-15cm of new snow creating a dense wind slab above treeline, This wind slab ranges from 10-50cm thick and overlay a very loose faceted snowpack creating a weak interface that produced easy results in our snowpack tests. The Nov crust is still present ranging from 30-80cm deep and not currently reactive.
Avalanche Summary
Increase avalanche activity today, natural and skier trigger avalanches to size 2 on wind affected slopes. Releases are failing on the wind slab facet interface and possibly entraining loose facets from deeper in the snowpack. Though the wind slab is the primary concern we suspect loose dry avalanches are still prevalent in steep alpine terrain.
Problems
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 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.