Careful snowpack evaluation, cautious route-finding and conservative decision making is essential until the storm snow settles.
There are buried persistent weak layer (PWL) 's down more than 60cm in the snowpack. Depending on aspect and elevation, there may be suncrust, facets and/or surface hoar lurking in the mid-upper snowpack. There's potential for step-down avalanches if storm slabs in motion trigger these layers.
Recent new snow along with strong SW winds, has created a widespread storm slab that is reactive on all aspects and elevations. Natural avalanches are possible and human-triggered avalanches are likely.
Thursday's storm triggered a few natural avalanches in the hwy corridor, up to size 2.5. Avalanche control Thursday produced widespread results, triggering avalanches up to size 3.0.
Before Thursdays snowfall, large avalanche debris and fracture lines could be seen in most avalanche paths from last weekends storm. The natural avalanche cycle had avalanches up to size 4, running full path.
A group up the Asulkan had 1 skier partially buried in a size 2 avalanche Sunday.
Up to 20cm of new snow fell Thursday, with strong SW winds. This covers up to 80cm that fell last weekend, accompanied by periods of extreme SW winds. This slab sits on old breakable crust &/or surface hoar (3-10mm, largest in the alpine).
Two persistent weak layers (PWL) in the heavily facetted snow from cold temps in Jan/Feb are now buried well over a meter. Large triggers such as storm slab avalanches in motion may step-down to these layer.
A weak ridge gives mixed sun and cloud, with cooling temps heading in to the weekend.
Tonight Clear. Alpine low -11°C. Ridge wind SW 15km/hr. Freezing level (FZL) valley bottom.
Sat 7cm. Alpine high -7°C. SW wind 25-60km/hr. FZL 1400m.
Sun 7cm. Low -11°C, High -7 °C. SW wind 20-35km/hr. FZL 1200m.
Mon 7cm. Low -12°C, High -8°C. SW wind 15-30km/hr. FZL 1200m.
