Thursday should be a relatively cool and dry day compared to what is on the horizon for the weekend.
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
Synopsis: A series of frontal systems will affect the south coast over the next few days but its hard to say how much precipitation will spill over inland. The first and weakest system grazing us tonight and Thursday morning. Freezing levels should stay near 1000 m. The next stronger system will arrive on Friday bumping freezing levels to 2000-2300 m and dropping moderate snow or rain. Winds also increase to strong from the S-SW. One last blast on Saturday will bring more rain or snow and strong ridge winds with a freezing level up to 2500 m.
Avalanche Summary
Several natural wind slab avalanches were reported during and at the end of the recent storm (ending early Monday). On Monday one natural size 3 avalanche and one size 1.5 accidentally triggered avalanche were reported from the South Chilcotin Mountains. These were both wind slabs on northerly aspects near ridge top. Numerous size 1-2 loose wet slides were observed in the Coquihalla on Tuesday.
Snowpack Summary
A sun crust or surface hoar now caps the 30-50 cm of previous storm snow. Deep and dense wind slabs in are likely in exposed wind-affected terrain from strong W-SW winds. The fresh storm and wind slabs overlie a hard crust and/or surface hoar layer. The bond to the crust could be somewhat variable but many observers report a good bond. Where surface hoar is present (possibly above the crust) the storm slab has been more reactive to ski testing on steep unsupported features. Deeper snowpack weaknesses are still on our radar, but seem to be dormant for the time being.
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.