Regions
Banff Yoho Kootenay.
We expect a natural avalanche cycle to start Wednesday and last for the next 48 hours. SH
Weather Forecast
West winds up to 110km and 30+cm of snow is forecast Wednesday at higher elevations, with highest amounts along and West of the divide Freezing levels are expected to rise to 1900-2000m over the next 24hrs and remain there until Friday. We could see some rain in areas such as Field and Kootenay as freezing levels rise.
Snowpack Summary
A field trip to Kootenay found a well settled 2m snowpack at 2000m with the only compression results in the top 15cm of loose storm snow. 10cm supportive rain crust to 1800m in that area. This is a stark contrast to thinner snow pack areas which have storm slabs and wind slabs 30-40cm thick sitting over a mainly facetted snowpack.
Avalanche Summary
Ski cutting produced small but far running sloughs in steeper terrain today within the top 15-20cm of snow. The sloughs ran for approx. 200m. No other avalanches reported or observed.
Confidence
Forecast snowfall amounts are uncertain on Wednesday
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.