Avalanche Forecast

Issued: Jan 19th, 2018 5:11PM

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

Avalanche Canada cgarritty, Avalanche Canada

For the safest, best skiing and riding, seek out low density new snow that hasn't formed a slab. Increase your caution at sheltered mid elevations where buried surface hoar may lurk.

Summary

Confidence

Moderate -

Weather Forecast

Saturday: Cloudy with scattered flurries bringing 2-5 cm of new snow, continuing overnight. Light to moderate southeast winds. Alpine high temperatures around -5.Sunday: Mainly cloudy with continuing isolated flurries and a trace of new snow. Light to moderate east winds. Alpine high temperatures around -7.Monday: Cloudy with flurries bringing approximately 5 cm of new snow. Moderate south winds. Alpine high temperatures to about -7.

Avalanche Summary

Reports from Thursday included observations of several storm slabs releasing naturally, remotely (from a distance), and with skier traffic. Avalanche sizes ranged from Size 1-2. The remote release was noted to have slid on lower angle terrain over a surface hoar on crust 'combo' left behind by the recent inversion. Ski cutting in the Shames area also produced loose wet releases to Size 1 in steep terrain. Looking forward, the storm slabs that formed over Thursday may remain reactive to human triggering on Friday. Sheltered openings at mid elevations are an emerging concern with reports indicating they may harbour a touchy layer of surface hoar beneath the new snow.

Snowpack Summary

Snowfall over the mid-week brought about 30 cm of new snow to the region. Northern parts of the region saw about half this amount. The new snow has buried a mix of old wind slabs and temperature crusts left over from the weekend. More isolated surface hoar has been observed under the new snow at mid elevations that experienced cloud cover during recent inversion conditions. Storm slabs have been particularly reactive where this surface hoar exists.Professionals have been monitoring a few layers in the upper snowpack, including crusts and surface hoar layers buried 40-80 cm below the surface. Although these layers have been reactive in recent snowpack tests, they have not produced avalanches lately. The lower snowpack is generally strong, with the exception of areas around Stewart and further north where a basal crust and facets exist.

Problems

Storm Slabs

An icon showing Storm Slabs
Recent snowfall has formed storm slabs over widespread temperature crusts and more isolated pockets of surface hoar. Slabs are likely to be touchiest where surface hoar is buried and in the immediate lee of ridgecrests and exposed terrain features.
Use ridges or ribs to avoid steep pockets of wind loaded snow.Sheltered openings at mid elevations are likely areas for surface hoar to be preserved.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 20th, 2018 2:00PM

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