Northwest Coastal

Strong winds continue to redistribute recent snow loading lee features and cross-loaded terrain. With more snow falling Monday, the storm slab trend continues.

Low - Due to the number of field observations

SUNDAY NIGHT: Mostly cloudy. Moderate southwest wind. Alpine low temperature -5C, freezing level 600 m.MONDAY: Snow, 10-20 cm with accumulation starting later the day. Moderate south-southwest winds gusting strong. Alpine high temperature -3C, freezing level 700 m..TUESDAY: Snow, 20-30 cm. Moderate south-southwest wind gusting strong. Alpine low temperature -4C, freezing level rising to 1000 m.WEDNESDAY: Cloudy with isolated flurries, trace accumulation. Light west wind with moderate gusts. Alpine high temperature +1C, freezing level 1300 m.

No avalanches were observed in most of the region over the last few days, but a MIN report from the Wolf's Den north of Terrace reports strong ridgetop winds redistributing snow and slab properties in the snowpack (see the MIN here) .On Wednesday in the far north near Ningunsaw, two large (size 2 and size 3) remotely (from a distance) triggered persistent slabs were observed failing over a 20-50 cm-deep layer of surface hoar over crust. This problem is likely isolated to the far north of the region, but may also exist on sheltered high elevation slopes elsewhere in the region.

20-30 cm recent snow is being redistributed by westerly winds forming hard slabs and loading snow in lee and cross loaded terrain. This snow covers a variable surface of wind-affected and faceted snow, a weak layer of surface hoar in more protected areas, and a rain crust/surface hoar combination below 1500 m. Rain has saturated the snowpack below 600 m. Below the new snow interface, old wind-affected storm snow is expected to have formed a good bond with the underlying snowpack. An exception to this 'good bond' may exist in some sheltered higher elevations that were unaffected by rain during the storm. Here, the old storm snow described above may overlie a weak layer of surface hoar (feathery crystals). This layer was identified as the failure plane in several recent large avalanches in the north of the region. It has not shown in reports elsewhere.For most of the region, a weak layer of facets (sugary snow) buried in early December exists down 180-250 cm. The likelihood of triggering this layer is decreasing, but it could be triggered by humans in shallow snowpack areas, particularly in the north of the region.