It's getting trickier, the new snow and wind Thursday night should continue to form easily avoidable storm slabs, but we're not sure if this will worsen the persistent slab problem. Best to continue to stay conservative with terrain selection Friday.
Summary
Confidence
Low - Forecast snowfall amounts are uncertain
Weather Forecast
Most of BC finds itself under the influence of a massive arctic high pressure system that has enveloped much of the province (and western Canada) in an unseasonably cold, dry arctic air mass. In contrast, a milder, moisture laden stream of air has taken aim at southwestern BC. These two air masses are set to clash over southern BC through Friday night producing a cold snowy pattern for the southern interior. THURSDAY NIGHT: Freezing level at valley bottom, strong to extreme west/northwest wind at ridgetop. 5 to 20 cm of snow possible. FRIDAY: Overcast, freezing level at valley bottom, strong northwest wind, trace of snow possible. FRIDAY NIGHT: Freezing level at valley bottom, 5 to 20 cm of snow possible. SATURDAY: Skies clearing throughout the day, freezing level at valley bottom, moderate northwest wind, 1 to 10 cm of snow possible.SUNDAY: Clear skies, freezing level at valley bottom, light variable wind, no snow expected.
Avalanche Summary
On Wednesday reported avalanche activity was limited to sluffing from steep terrain. On Tuesday, a skier triggered a size 1.5 wind slab on a north-facing alpine slope in Kokanee Glacier Provincial Park. The skier went for a short ride, but was uninjured in the event. No other recent avalanches have been reported. As new snow accumulates over the next few days, fresh wind slabs should remain on your radar. More importantly, the December 15th interface will become deeper. With that, the overlying slab may settle and gain cohesion increasing the likelihood of triggering of this buried persistent weak layer.
Snowpack Summary
As of Thursday afternoon the storm has produced 10 to 20 cm of low density snow which has been accompanied by light to moderate wind out of south, southwest and even a bit of of southeast. The new snow overlies recently buried surface hoar, although at this point not much is known about the size or distribution of this potential weak layer.Between 30 and 85 cm below the surface you'll find the December 15th interface which consists of a melt-freeze crust on steep, solar, higher elevation slopes and well-developed surface hoar which seems most pronounced in sheltered treeline terrain and below. The bond at this variable interface is of critical importance, especially in areas where the overlying slab is deep and well-consolidated.The late November crust is now buried 60-100 cm and has been producing hard, resistant results in recent snowpack tests. Beneath this crust the lower snowpack is strong and well-settled.
ghelgeson,
Avalanche Canada
