The primary concerns are new wind slabs forming up high and the potential of triggering buried weak layers.
Wind slabs may have formed from northeast wind and continue to form on Thursday as the wind shifts to the southwest. Slabs could slide easily and travel far, as they may overly weak surface hoar.
Numerous weak layers may exist in the top half of the snowpack, including surface hoar and faceted grains over a melt-freeze crust. These layers were recently triggered in riding areas north of Terrace and the likelihood remains for avalanche activity anywhere these layers exist.
WEDNESDAY NIGHT: Partly cloudy, 10 to 20 km/h northwest wind, alpine temperature -4 C.
THURSDAY: Cloudy, 20 to 40 km/h southwest wind, alpine temperature -4 C.
FRIDAY: Cloudy with snowfall, accumulation 20 to 40 cm, 40 to 60 km/h southwest wind, alpine temperature -4 C.
SATURDAY: Cloudy with snowfall, accumulation 20 to 40 cm, 60 km/h southwest wind, alpine temperature -5 C.
The most prominent recent avalanche activity includes human-triggered avalanches north of Terrace. It is suspected that they released on the weak layers described in the snowpack summary. The likelihood of humans triggering similar avalanches remains. Check out these three MIN's for further information: here, here, and here.
Otherwise, a few small (size 1) storm slab avalanches were triggered naturally and by explosives in the top 5 to 15 cm of the snowpack.
Around 10 to 15 cm of snow fell on Wednesday with moderate northeast wind that is forecast to shift to the southwest. Expect to find wind slabs in exposed terrain features. The snow may overly feathery surface hoar so it could slide easily and travel far. The surface hoar was reported as being widespread. There may be a melt-freeze crust directly beneath the surface hoar.
Another weak layer surface hoar may be found around 30 to 60 cm deep. The most likely places to find this layer would be in terrain features sheltered from wind effect. Around 100 to 200 cm deep, a hard melt-freeze crust from early December may have weak and sugary faceted grains around it. These weak layers are likely the culprit of recent avalanche activity in the Nass Valley, Sterling, and Beaupre riding areas.
The early-November melt-freeze crust is over 200 cm deep and may have faceted grains above it in parts of the region, particularly in the north. The last reported avalanche activity was near Ningunsaw on December 11.
