The recent storm delivered a substantial storm slab problem to the alpine while soaking lower elevation terrain. Be aware of increasing hazard as you transition to higher elevations.
Weather Forecast
Friday: Mainly cloudy with isolated flurries and a trace of new snow. Winds light from the southeast. Freezing level to 1200 metres with alpine temperatures of -5.Saturday: Mainly cloudy with isolated flurries and a trace of new snow. Winds light from the southeast. Freezing level to 1000 metres with alpine temperatures around -6.Sunday: Cloudy with scattered flurries and a trace of new snow. Winds light to moderate from the southeast. Freezing level to 1000 metres with alpine temperatures around -6.
Avalanche Summary
Reports from Wednesday include numerous storm slabs releasing naturally as well as with explosives and ski cutting to Size 2 in the Whistler area. Ski cut Size 1 slabs were noted running slowly over long distances. Thursday's reports included evidence of a natural Loose Wet avalanche cycle to Size 1.5 below 1900 metres in the Whistler area.
Snowpack Summary
A trace of new snow dusted the surface at treeline elevations over the day on Thursday, with wet flurries and rain continuing at lower elevations. This change follows rain which fell to 2000 m during the day on Wednesday. The mix of rain and new snow has landed on either wind slabs in the alpine or temperature crusts at treeline and below, especially on east and south aspects. Both of these surfaces will be good sliding layers for incoming snowfall.The mid and lower snowpack are generally well settled and strong. However, there remain a number of facet and crust layers (down 60-80cm in shallower areas) that are currently dormant but will require monitoring with additional loading (and warming this week), especially in the shallow, rocky areas.
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.