Recent wind slabs will be gaining strength but may become unstable with solar radiation on Wednesday.
Confidence
High - The weather pattern is stable
Weather Forecast
Wednesday: Sunny. Winds light from the northeast with occasional strong gusts. Freezing levels to 200 metres and alpine temperatures to -2.Thursday: Cloudy with sunny periods. Winds light to moderate from the west. Freezing level near valley bottom with alpine temperatures to -3.Friday: Cloudy with scattered flurries and up to 5 cm of new snow. Winds moderate from the southeast. Freezing level rising to 400 metres with alpine temperatures of -2.
Avalanche Summary
Ski cutting in the North Shore mountains on January 1 produced one size 1 wind slab avalanche 10 metres wide and 20 cm deep. Shooting cracks were propagating up to 2 metres ahead of ski tips on wind loaded features, suggesting touchy conditions at the time. While we normally expect a short life span these kinds of instabilities on the South Coast, cold temperatures may be preventing our current wind slabs from bonding to underlying snow at the usual rate.
Snowpack Summary
Strong northerly winds have redistributed loose snow from recent storms into wind slabs behind exposed terrain features on southerly aspects, including both southwest and possibly southeast slopes. Approximately 95 cm of well-settled storm snow lies on the surface and has bonded well to the underlying snow. While snowpack tests have revealed no significant instability within the storm snow, the spatial variability of wind slab instabilities may be a limiting factor. Aside from wind slab instabilities in the upper snowpack, the mid and lower snowpack are considered to be well settled and stable.
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.