Regions
Kootenay Boundary.
A storm is expected to start late on Thursday. If it comes early, danger may increase during the day on Thursday.
Confidence
Moderate - Timing of incoming weather systems is uncertain on Thursday
Weather Forecast
Thusrday during the day is expected to be mostly dry, with light southwest winds and treeline temperatures around -12C. New snow is expected to start late on Thursday and continue overnight bringing around 15-20 cm of low density snow by Friday morning. A further 5-10 cm is expected through the day on Friday acompanied by 40-60 km/h southwest ridgetop winds and treeline temperatures rising to around -4C in the afternoon. On Saturday, light snow (2-5 cm) is expected with light southwest winds and treeline temperatures around -5C.
Avalanche Summary
Only sluffing of the new snow in steep terrain has been reported since the weekend.
Snowpack Summary
Recent light snowfall has added around 10 cm or so to the previous storm's 20-50. This puts around 30-60 cm recent snow sitting above a thick rain crust. Reports indicate wind loading occurred on north aspects during the storm and then subsequently on southern aspects as the wind shifted around to the north. The crust in the upper snowpack can be found as high as 2400m. At treeline elevation it is thick and supportive, and should be capping any deeper weaknesses. The weak layer from early December has recently become inactive, likely due to all the moisture in the snowpack and subsequent settlement and re-freezing.
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.