Avalanche Forecast

Fair - Timing, track, or intensity of incoming weather system is uncertain

A weak storm system reaches the South Coast late Friday or early Saturday morning.15-25mm of precipitation are possible for much of the region on Saturday. Freezing levels should peak at around 1000m and alpine winds are expected to be moderate-to-strong from the NW. A ridge of high pressure builds on Sunday and will persist for several days. Sunday should be mostly clear and dry with freezing levels around 500m and light alpine winds. Monday should be pretty much the same with colder temperatures.

No new observations on Thursday or by publish-time on Friday. On Wednesday, a snowmobiler was involved in an avalanche in the Callaghan area. Details are limited but it sounds like an isolated storm instability was the main problem. On Tuesday, several natural size 1 wind slabs were reported.

The snow surface prior to the storm includes wind scouring or old wind slabs in exposed terrain, and well settled storm snow in sheltered areas.  On top of these surfaces is widespread surface hoar layer up to 10mm in size.  40-60cm below this is the mid-December surface hoar layer. This layer appears to have gained strength and stabilized in most of the region but still may be a concern in the northern parts of the region. Reports suggest that the surface hoar is most prevalent on sheltered north aspect slopes at treeline elevation. Winds prior to burial likely destroyed the surface hoar in the alpine throughout most of the region. The mid and lower snowpack contain several old crust layers but these have generally been unreactive.