Regions
Kootenay Boundary.
Confidence
Fair - Wind effect is extremely variable
Weather Forecast
Generally clear conditions are expected for the forecast period. Winds are forecast to be mainly moderate from the northeast. Alpine temperatures should hover between -20 and -25 for Tuesday and Wednesday with some very slight warming on Thursday.
Avalanche Summary
On Monday whumphing, shooting cracks and size 1 wind slab avalanches were observed at all elevation bands in the Kootenay Pass area.
Snowpack Summary
About 25cm of low density snow now overlies well developed surface hoar which exists on most aspects, and in some cases, well into the alpine. Below this you'll likely find about 10cm of faceted snow over older surface hoar and old, unreactive wind slabs. A melt-freeze crust is now buried on most slopes that saw direct sun last week.Reports indicate the low density surface snow has been wind-pressed or redistributed into wind slabs in many places. I'd expect touchy slab conditions due to the presence of buried surface hoar anywhere where there was significant wind effect.The recent prolonged warm temperatures have formed a strong and supportive midpack. Deeper persistent layers have become unlikely to trigger, although large and destructive avalanches are still possible in isolated terrain with the right input such as a cornice fall or a heavy load over a thin spot in steep 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.