http://www.pc.gc.ca/apps/scond/Cond_E.asp?oID=22583&oPark=100205Expect the surface slab buried surface hoar layer combo to be sensitive to human triggering today.
Weather Forecast
Cooler temperatures, light flurries and light ridge top winds with sunny breaks are forecast for today. More flurries, temps in the -6C range and light west winds for Monday. Watch for solar impacts on surface instabilities on steeper S through SW aspects today.
Snowpack Summary
Warm temperatures, upwards of 35cm storm snow and a persistent weak layer resulted in an avalanche cycle yesterday. Cooler temperatures and the end of precipitation should have slowed the natural cycle however human triggering is a real concern. Overnight 7hrs of moderate S winds will have formed soft slabs on alpine and treeline lee features.
Avalanche Summary
A natural avalanche cycle occurred yesterday with slides up to size 3.5. Of note, Frequent Flyer produced a size 3.0 slide running down past the creek and up onto the bottom of Cheops. Most of the north Cheops paths also released. Avalanche control along the highway corridor produced numerous slab avals in the 2.5 to 3.5 size from all aspects.
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.