Avalanche Forecast

Issued: Apr 21st, 2017 4:02PM

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

Avalanche Canada cgarritty, Avalanche Canada

Dynamic conditions prevail in the South Coast mountains. Warm overnight temperatures will keep cornices weak before colder temps set in and fresh wind slabs begin to build on Saturday afternoon.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Saturday: Mainly cloudy with rain showers transitioning to flurries in the evening and periods of snow overnight. Up to 5 cm accumulating at higher elevations by the end of the day. Moderate southwest winds. Freezing level dropping to 1500 metres over the day with alpine temperatures from 0 to -3.Sunday: Cloudy with flurries bringing up to 5 cm of new snow. Light south winds. Freezing level to 1500 metres with alpine temperatures of -4.Monday: Mainly cloudy with isolated flurries and a trace of new snow. Light southeast winds. Freezing level to 1600 metres with alpine temperatures of -3.

Avalanche Summary

No new avalanches have been reported, but there have been limited observations lately.Please enter your observations on the Mountain Information Network (MIN). See here for details.

Snowpack Summary

Friday's warm temperatures and sunshine moistened surface snow on most aspects and elevations. Warm overnight temperatures will prevent it from refreezing into a solid crust. Below the surface, stormy weather over the beginning of this week brought about 50mm of precipitation to the North Shore Mountains, most of which fell as rain to the summits. In the Sky Pilot area, 30-40cm of snow likely fell above 1600m and was redistributed into wind slabs in lee terrain by recent southeast winds. Cornices also gained fragile new growth over the same time period. Below the wind effect, the new snow is now forming a good bond to the underlying crust. The mid and lower snowpack are well settled and strong.

Problems

Cornices

An icon showing Cornices
Where cornices exist, they have become unstable should be avoided. After warm temperatures on Friday, cornices need a good refreeze to regain some strength. This refreeze won't set in until late Saturday.
Stay well to the windward side of corniced ridges.Avoid traveling on slopes that are exposed to cornices overhead.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

An icon showing Wind Slabs
Fresh wind slabs will begin building on Saturday as another storm rolls in.
Be especially careful with wind loaded pockets near ridge crests and roll-overs.Be increasingly cautious as you transition into wind affected terrain.

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 22nd, 2017 2:00PM

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