Regions
Kootenay Boundary.
Caution as you transition into wind affected terrain, as lingering wind slabs exist.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
THURSDAY: Mix of sun and cloud, light south winds, alpine temperatures at -15.FRIDAY: Flurries with accumulations of 5-10 cm, 20-40 southwest winds, alpine temperatures at -15.SATURDAY: Isolated flurries, light west winds, alpine temperatures at -12.
Avalanche Summary
Small loose dry avalanches have been reported in steep terrain the past few days. Cornice control on Tuesday triggered a size 3 wind slab on a very steep cross-loaded northeast slope at treeline (See the YAMMY report on the MIN). This report is a good reminder that although there have been few reports of wind slab avalanches recently, it is critical to identify wind loaded terrain features
Snowpack Summary
25 cm of low density snow from last weekend sits above a thin drizzle crust in many places and is gradually settling. Northerly winds have redistributed the snow, forming stubborn wind slabs in exposed areas. New surface hoar up to 10 mm in size has been reported growing on the surface, and will continue to develop during this fair weather period. Watch for slopes that develop surface hoar or surface facets, because new snow will bond poorly when the next storm arrives. A thick melt-freeze crust from mid-November is buried 40-80 cm deep. Facets have recently been reported above this crust and may continue to develop with the cold temperatures. Facet growth will be most pronounce in shallow alpine start zones, creating the potential for large avalanches in the future. Snowpack depths are 130-160 cm at treeline elevations.
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.