Watch for fresh wind slabs at upper elevations and be mindful of the potential for wind slab avalanches to step down to deeper weak layers.
If you see more than 15 cm of new snow in the Coquihalla area on Sunday morning, treat avalanche danger as CONSIDERABLE in the alpine.
Small inputs of new snow with wind overnight have likely formed fresh and reactive wind slabs. Older wind slabs have been reactive especially to skier traffic, on a variety of aspects due to variable wind direction.
Weak layers of surface hoar and/or faceted grains may be found above a hard melt-freeze crust. Recent reports suggest the weak layers may be less prevalent in the south of the region, but still exist in localized pockets.
Saturday night: Up to 5 cm new snow, strong southwest wind easing to moderate, freezing level 500 m.
Sunday: Sun and cloud, light southwest wind, alpine temperature -7 C, freezing level 700 m.
Monday: Sun and cloud, light northwest wind, alpine temperature -3 C, freezing level 500 m.
Tuesday: Sunny, light northwest wind increasing to moderate southwest, alpine temperature -5 C, freezing level 300 m.
Numerous skier triggered wind slab avalanches size 1-2 have been reported throughout the region over the last week. Typically they are being triggered on wind loaded convex terrain features at alpine and treeline elevations.
A few persistent slab avalanches have been triggered in the past week, mostly in the north of the region near the Hurley, but also near Allison Pass. They were triggered by riders, heavy machinery, and naturally. The slabs were generally 60 to 90 cm deep, around 2000 m, and released on the weak layers described in the snowpack summary.
5-10 cm of new snow has been redistributed by strong overnight wind. Below treeline, the recent snow may be sitting over surface hoar.
A hard melt-freeze crust from early December is found around 40 to 120 cm deep in the snowpack. This crust may have weak layers above it, consisting of feathery surface hoar or sugary faceted grains. These weak layers are most prevalent in the north (e.g., Duffey Lake, Hurley) and found to a lesser extent in the south of the region. The snowpack should be treated as suspect anywhere you find either surface hoar or faceted grains above the crust.
The remainder of the snowpack is well-settled in the south of the region. In the north, another melt-freeze crust with associated faceted grains around it may be found near the ground. Without evidence of recent avalanche activity, the layer appears to be dormant at this time.
