A widespread natural avalanche cycle is expected to continue through to Saturday evening. Areas that have previously avalanched are reloading.
Weather Forecast
Light precipitation is forecast to continue through the day accompanied by moderate to strong South through West winds and an alpine high of -7C. Tonight cold air will invade with temperatures dropping into the -22C range accompanied by moderate Easterly winds and a trace of precipitation.
Snowpack Summary
At 1900m upwards of 75cm of storm snow has fallen in the past 48hrs with mod to strong S'ly winds. New snow sits atop hard wind slabs in the alpine and Jan 31 surface hoar at and below treeline. January 17 surface hoar is buried 70cm and is most reactive between 1400-1900m, and where it overlies a crust on steep solar aspects.
Avalanche Summary
A widespread avalanche cycle occurred yesterday and is expected to continue today with more snow and moderate to strong S through W winds. Avalanche control through the highway corridor produced numerous avalanches to size 3. Limited backcountry observations however Frequent Flyer was reported to have released to size 3 in the middle of the storm.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
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.
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.