Regions
South Coast Inland.
If Friday night's storm arrives early, the avalanche danger may be higher than posted.
Confidence
Moderate - Timing of incoming weather systems is uncertain on Friday
Weather Forecast
Friday: About 5cm of the new snow with an additional 10-15cm overnight / Moderate southwest winds / Freezing level at 600mSaturday: Mix of sun and cloud / Light southwest winds / Freezing level at 1400mSunday: Mostly clear skies / Light southwest winds / Freezing level at 2300m
Avalanche Summary
No new avalanche activity was reported on Tuesday or Wednesday. A new round of storm slab activity is expected on Friday afternoon and into Saturday with forecast wind and snow.
Snowpack Summary
20 to 40 cm of recent storm snow (with more in the Coquihalla area) now rests on the the January 6th crust. This crust formed after temperatures cooled last Saturday, locking up the previously moist surface snow. On Sunday moderate to strong southwest winds redistributed snow and formed wind slabs in lee features at and above treeline. A widespread melt-freeze crust formed in mid-December is still an issue in the northern portion of the region where it is down 40 to 50 cm below the surface. Recent observations have shown that there are rounding facets underneath the crust on shady aspects at and above treeline. Recent snowpack tests have produced easy sudden-planar results on solar aspects at and above treeline on this interface as well. Around the Coquihalla this interface is not problematic and is thought to be part of a well bonded mid-pack. The lower snowpack is generally strong and well settled.
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.