Avalanche Forecast

- Forecast snowfall amounts are uncertain

SUNDAY NIGHT: Cloudy with isolated flurries, trace accumulation Moderate west wind. Alpine low -8C, freezing level below 500 m.MONDAY: Flurries, 5-15 cm accumulating by end of day. Moderate southwest winds gusting to extreme. Alpine high -7C, freezing level 1000 m.TUESDAY: Snow, 5-15 cm, Moderate to strong west winds. Alpine high -3C, freezing level 1100 m.WEDNESDAY: Mainly cloudy with isolated flurries, trace accumulation. Light to moderate west-northwest wind. Alpine high -2C, freezing level 900 m.

On Friday, a size 2 avalanche was observed on a southeast aspect just below the ridgeline (see MIN report here). Winds have recently shifted more westerly, and cross-loading and variable wind transport has likely contributed to winds slabs on all aspects in the alpine and treeline.A large (size 2) persistent slab avalanche was remote (from a distance) triggered in the Kispiox area on Tuesday. It released over a buried layer of faceted (sugary) snow on a mellower (30 degree slope) southeast aspect at 1680 metres. This avalanche stands out from recent reports for the presence of a persistent weak layer at the failure plane, as well as for its remote trigger on a fairly mellow slope. Although it appears to be an isolated incident, it highlights the presence of a buried persistent weak layer that may remain preserved in northern parts of the region. Images of the slide suggest that wind loading was another contributing factor.

15-30 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. Below this new snow interface, 25-50 cm of affected storm snow from over a week ago is expected to have formed a good bond with the underlying snowpack. A few buried weak layers that consist of surface hoar (feathery crystals) and/or faceted (sugary) snow may exist in some sheltered areas. The upper layer is about 35-60 cm deep and is a possible culprit in the Kispiox avalanche noted above. The next layer is likely 65-90 cm deep. The lower one is now approximately 100-150 cm deep.The bottom 30 to 50 cm of the snowpack consists of facets and crusts, particularly in areas where the snowpack is thin. It may be possible for storm slab avalanches to scrub down to ground in thin snowpack areas, resulting in large avalanches.