Avalanche Forecast

Issued: Jan 16th, 2019 4:55PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada cgarritty, Avalanche Canada

Solar warming and wind loading are the weather factors to watch for on Thursday. Seek out shaded areas outside of wind effect for the best quality and safest skiing and riding.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Wednesday night: Cloudy below about 1900 metres, clear above. Moderate southeast winds.Thursday: Cloudy below about 1900 metres, sunny above. Moderate southeast winds. Alpine high temperatures around -8, cooler at lower elevations due to an alpine temperature inversion.Friday: Mainly cloudy with scattered flurries bringing 2-5 cm of new snow over the day, continuing overnight. Light to moderate southeast winds, increasing to strong in the alpine. Alpine high temperatures around -5 with a possible lingering temperature inversion.Saturday: Cloudy with flurries bringing about 5 cm of new snow and new snow totals to 10-15 cm. Strong southeast winds shifting southwest. Alpine high temperatures around -4.

Avalanche Summary

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, expect wind slabs to remain triggerable on sun-affected and wind-loaded slopes.

Snowpack Summary

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. 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.

Problems

Wind Slabs

An icon showing Wind Slabs
Older wind slabs will be most prevalent on north to east aspects, but shifting winds may form touchier new ones on west aspects.. South aspect slopes will be more prone to the effect of the sun.
Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 17th, 2019 2:00PM