Northwest Inland

Increasing winds and light snowfall are keeping our wind slab problem on life support in advance of the next storm pulse.

High -

Thursday night: Increasing cloud. Light southeast winds.Friday: Cloudy with scattered flurries bringing up to 5 cm of new snow, continuing overnight. Moderate to strong south winds. Alpine high temperatures around -5.Saturday: Cloudy with flurries bringing 2-5 cm of new snow, increasing overnight. Moderate to strong east winds shifting southwest. Alpine high temperatures around -6.Sunday: Cloudy with diminishing flurries bringing around 3 cm of new snow and new snow totals to around 15-20 cm. Moderate to strong southwest winds. Alpine high temperatures around -7

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 report of a persistent weak layer at the failure plane, as well as for its remote trigger on a fairly mellow slope. It remains to be seen whether it is an indicator of any emerging pattern, however images of the slide suggest that wind loading was a contributing factor and reinforce the need for avoidance of wind-loaded areas.The weekend's avalanche activity from the Microwave area near Smithers is documented well in these two MIN posts here and here. Storm slab avalanches up to size 2 were observed on north aspect slopes. Thanks a tonne to the riders who submitted these observations.Looking forward, watch for light new snow amounts being blown into thin but touchy new wind slabs progressively over the day on Friday..

The storm that ended late on Saturday produced 25 to 50 cm of new snow at higher elevations, with rain falling up to 1500 m. Strong winds redistributed the storm snow at and above treeline. The snow at lower elevations is now most likely crusty.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 was the likely 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.