Incoming precipitation with strong S-SW winds will create wind-slabs at treeline and above on existing crusts. Surface hoar has formed in protected locations. Careful terrain evaluation will be important during this next storm cycle
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
A fast moving cold front moves inland today bringing strong southwest winds and precipitation to the South Coast Inland area. 10 to 20cm of snow forecast for upper elevations. Saturday there will be a small break in the weather with another 10 to 20cm on Sunday. Freezing levels will fluctuate between 800 to 1500 metres as the storm moves through.
Avalanche Summary
No recent avalanches have been reported.
Snowpack Summary
New storm snow being redistributed by strong winds on top of the crust will be the situation to watch. There are a variety of layers previously mentioned in snowpack discussions, but unless there is an extreme weather event, they are likely to remain out of the picture for the time being. Surface hoar development has been reported on North aspects up to ridge tops. One operator reported that the Jan. 4th surface hoar layer may now be buried by as much as 20 to 40 cm.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.