50-80 cm of new snow and strong winds over the past three days have increased the avalanche danger, conservative terrain selection is critical
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Snowfall will continue through Saturday night bringing a total of 15-25 cm of new snow by Sunday morning. Sunday will have light flurries with accumulations up to 5 cm, treeline temperatures around -5, and light winds from the southwest. No precipitation is forecasted for Monday or Tuesday, as temperatures will drop and winds shift to the northwest.
Avalanche Summary
On Friday, a cycle of natural size 2 storm slabs was reported in southern parts of the region. Storm slabs were also reactive to ski cuts and skier triggering at treeline elevations on Friday and Saturday. The size and likelihood of storm slab avalanches will increase with the addition of new snow and sustained southwesterly winds.
Snowpack Summary
15-25 cm of new snow on Saturday brings the three-day storm total to 50-80 cm, with the greatest amounts northwest of Revelstoke in the Monashees. Sustained southwesterly winds have redistributed this new snow, forming extra deep pockets and very touchy storm slabs. The mid-November crust is now buried 60-100 cm deep, and although recent reports suggest the snow is bonding well to the crust, it could eventually develop into a persistent slab problem. Below the crust the snowpack is generally well bonded. Limited observations suggest snowpack depths are 100-160 cm at treeline. Snowpack depths substantially decrease below 1600 m.
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.