Sustained strong winds will accelerate slab formation and keep loading lee terrain even when the snow stops falling. Storm slabs should be primed for human triggering on Friday.
Summary
Confidence
Moderate -
Weather Forecast
Friday: A mix of sun and cloud with possible isolated flurries. Moderate southwest winds. Alpine high temperatures of -7.Saturday: A mix of sun and cloud. Moderate southwest winds. Alpine high temperatures of -7.Sunday: Mainly cloudy with scattered flurries and 1-4 cm of new snow. Strong southwest winds. Alpine high temperatures around -8.
Avalanche Summary
No new avalanches have been reported since Thursday's storm, but heavy snowfall has been obscuring visibility into most terrain. Looking forward, expect ongoing strong winds to continue loading lee aspects even as snowfall tapers off. These winds will also be promoting slab formation and reactivity.
Snowpack Summary
Up to 30 cm of new snow from Thursday has buried both a new layer of feathery surface hoar that has been developing in sheltered areas as well as sun crust on solar aspects. The new snow will need time to form a reliable bond to this previous surface. Beneath the new snow, recent strong winds (mainly from the southwest) scoured windward slopes and formed wind slabs that are now buried in lee terrain at higher elevations.An unstable weak layer from mid-December (predominantly feathery surface hoar crystals and/or a sun crust) is found at treeline and below treeline elevations. Slabs can fail easily on this layer, either naturally or with the weight of a person or machine. Deeper in the snowpack, an early-season rain crust and sugary facets exist. An avalanche in motion could step down to these deeper layers, creating a large and destructive avalanche. Although the snowpack structure is variable across the region, these persistent slab problems are generally widespread. Snowpack depths are across the region are similarly variable, but typically shallower in the east.
cgarritty,
Avalanche Canada
