http://www.pc.gc.ca/apps/links/goto_e.asp?destination=http://www.facebook.com/ParksMountainSafety/posts/768278099888848%E2%80%8EThe December 17 surface hoar layer remains the number one problem and requires careful decision making. New snow may conceal buried wind slabs in exposed areas.
Weather Forecast
Expect ongoing flurries today with accumulation up to 5cm. Ridge top winds will be southwest in the moderate range. Precipitation will ease off overnight as winds intensify. Saturday brings more light precipitation with strong winds. Watch for wind slab formation. The next major system will arrive late Sunday bring moderate amounts of snow.
Snowpack Summary
10cm of new snow now covers recently formed wind slabs in exposed areas and facets elsewhere. The Dec 17th surface hoar layer is down 60-80cm sitting on top of a thick rain crust facet combo below 2100m and sitting on a settled mid-pack above. This layer is widespread and continues to be reactive.
Avalanche Summary
Natural avalanche activity has decreased in recent days but this is likely to change. New overnight snow and wind will form touchy storm slabs on exposed features. There is now increased risk of avalanches stepping down 60-70cm to the December 17 surface hoar layer, which is still reactive to skier loads.
Problems
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.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.