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: Mainly cloudy with scattered flurries bringing around 2 cm of new snow, continuing overnight. Moderate south winds. Alpine high temperatures to around -6.Sunday: Cloudy with continuing flurries bringing 3-5 cm of new snow decreasing overnight. Moderate to strong east winds. Alpine high temperatures to -8.Monday: Cloudy with continuing light flurries and a trace of new snow. Light southeast winds. Alpine high temperatures to around -8.

Avalanche Summary

Reports from Thursday included one observation of numerous natural storm slab releases from Size 1-2 north of Kispiox. These were noted running on relatively low angle terrain and suspected to have released over a layer of surface hoar that may not be widely distributed. Another few Size 2 natural storm slab releases were noted in very steep north aspects around treeline elevations in the Howsons.Wednesday's reports included observations of thin (5 cm) storm slabs becoming highly reactive to skier traffic in the Howson Range, producing small remotely triggered (from a distance) and sympathetically triggered (by an adjacent release) slides. These small slabs were also running naturally in any terrain over a 37 degree incline.

Snowpack Summary

Snowfall from the mid-week brought a variable 10-20 cm of new snow to the region. The new snow has buried a temperature crust that likely exists well into the alpine. There are also reports of more isolated pockets of surface hoar beneath the new snow at lower alpine and treeline elevations. This surface hoar is noted in our avalanche activity discussion for having produced numerous storm slab releases in a localized area after the storm ended. Below the new snow interface, deeper weak layers in the snowpack include a few crusts and surface hoar layers that formed in early January and December. Most recent reports suggest the snow is well bonded to these layers, but snowpack tests in the north of the region have shown some easy results with sudden fracture character, suggesting that a dangerous persistent slab problem may develop as the mid and upper snowpack consolidate into a stiffer slab.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs have formed over widespread temperature crusts and more isolated pockets of surface hoar. Slabs are likely to be touchiest where surface hoar is buried as well as in the immediate lee of ridgecrests and exposed terrain features.
Sheltered openings at mid elevations are likely areas for surface hoar to be preserved.Avoid areas where the new snow feels stiff and slabby.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

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

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