Avalanche Forecast

Issued: Mar 3rd, 2017 4:53PM

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

Avalanche Canada cgarritty, Avalanche Canada

Don't let your guard down yet. A final storm pulse over Friday night will keep avalanche danger HIGH on Saturday. Conservative terrain selection remains essential.

Summary

Confidence

High -

Weather Forecast

Friday night: Periods of snow bringing approximately 10 cm of new snow. Strong southwest winds.Saturday: Cloudy with flurries bringing approximately 5 cm of new snow. Light to moderate southwest winds. Freezing level to 500 metres with alpine temperatures of -9.Sunday: Mainly cloudy with isolated flurries and a trace of new snow. Light to moderate southeast winds. Freezing level near valley bottom with alpine temperatures of -7.Monday: Mainly cloudy with scattered flurries bringing approximately 5 cm of new snow. Light to moderate southwest winds. Alpine temperatures of -9.

Avalanche Summary

Thursday's reports include observations of numerous storm slabs generally running Size 1-1.5. The majority of these were triggered naturally and with ski cutting, although one remotely triggered Size 1.5 was noted. Another notable occurrence was a loose dry avalanche running to Size 2.5 in the Valhallas. All aspects shared fairly equal representation, with natural and remote triggers more focused on north to east aspects.Reports from Wednesday included numerous storm slab, wind, slab, and loose dry avalanche observations, with both natural and ski cut triggers. These slides typically ranged from Size 1-2 with crown fractures generally in the 15-30 cm range. An observation of one of these deeper slides identifies our mid-February interface as the failure plane, with several similar reports coming from the adjacent North Columbias. Looking forward, the next storm pulse looks to be a bit colder but is still coming in with strong winds. Expect continuing human triggering potential within our storm slabs, especially as new snow and wind continue adding load to the snowpack.

Snowpack Summary

Stormy weather since Tuesday night has delivered a wide-ranging 40-85 cm of new snow to the region, with the greatest accumulations occurring in the Monashees. Moderate to strong southerly winds have accompanied the new snow, promoting wind slab formation in lee terrain at upper elevations. The new snow has buried widespread faceted surface snow as well as more isolated surface hoar to 4mm. A thin sun crust may exist below the new snow on steep solar aspects. About 65-120cm below the surface you'll likely find the mid-February interface which is composed of a thick rain crust up to about 1800 m, sun crusts on steep solar aspects, and spotty surface hoar on shaded aspects. This layer could develop into a persistent slab problem once the snow above it settles into a stiffer slab. The mid and lower snowpack are generally well settled and stable.

Problems

Storm Slabs

An icon showing Storm Slabs
Another pulse of snow and strong south winds over Friday night will promote continuing storm slab formation and especially touchy conditions on wind loaded lee aspects. The new snow will also be adding load to an already 'upside down' storm slab.
The new snow will require several days to settle and stabilize.Be alert to conditions that change with elevation.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Valid until: Mar 4th, 2017 2:00PM

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