Recently formed wind slabs may remain reactive to human triggers for several days. Continue to investigate the layer of surface hoar down 60-120 cm.
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Sunday: Mostly sunny / Light to moderate easterly winds / High of -19 C.Monday: Sunny / Light northeasterly winds / High of -15 C.Tuesday: Sunny / Light northeasterly winds / High of -15 C.
Avalanche Summary
Wind slab avalanches are a concern in all areas within the region, and could easily step down to the surface hoar layer below. This surface hoar layer may remain reactive to human triggers for a longer period than is common for this region because it is being well preserved my cold temperatures.
Snowpack Summary
Clear skies and strong outflow winds have created a variety of snow surfaces including scouring and hard wind slabs in exposed areas and up to 12 mm surface hoar formation in sheltered areas. Strong to extreme easterly winds over the past few days have created wind slabs on aspects you may not expect them. Wind slabs could be present on all aspects in exposed alpine, treeline, and even some below treeline locations. A layer of surface hoar which was buried around November 22nd is down 60-120 cm in many parts of the region. This layer is likely still reactive to human triggers. A thick rain crust exists 20-30 cm below the surface hoar layer, with isolated reports of weak facets (sugary snow) forming above the crust; however, that interface has not become a concern as of yet. Treeline snow depths are around 140-200 cm in the Terrace and Stewart areas, but substantially less further north. Concerns in the north are basal weaknesses that may exist in the shallower snowpack areas especially on smooth alpine features like glaciers.
jsmith,
Avalanche Canada
