Regions
Northwest Coastal.
Triggering wind slabs remains possible in exposed terrain. Watch for signs of unstable snow such as cracking or hollow sounds.
Confidence
Moderate - Wind speed and direction is uncertain
Weather Forecast
TUESDAY: Mix of sun and cloud, moderate northwest winds, treeline temperatures around -12 C.WEDNESDAY: Mostly sunny, light winds, treeline temperatures around -15 C.THURSDAY: Mix of sun and cloud, moderate west winds, treeline temperatures around -18 C.
Avalanche Summary
A skier remotely triggered a large (size 2) wind slab in the Shames backcountry area on Sunday. The avalanche started on a steep south-facing rocky ridgetop at 1400 m. Wind slabs were reported to have been building quickly in the area at the time and were reactive to skier traffic.
Snowpack Summary
Strong outflow winds dramatically affected the surface snow, scouring some slopes down to an old crust and forming hard deposits in many other areas. Sheltered areas may still have 20-40 cm of powder from previous storms, but winds have come from a variety of directions and affected much of the terrain. Wind slabs rest on a variety of old surfaces including a thick melt-freeze crust. In some sheltered locations, soft feathery surface hoar crystals may sit above the crust.The snowpack is reported to be generally strong below this crust, with the possible exception of areas around Stewart and northern parts of the region where the late October crust can be found deep in the snowpack. This deep crust has been been associated with weak sugary snow and could possible be triggered in shallow snowpack areas.
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.