Avalanche Forecast

Issued: Apr 8th, 2017 4:25PM

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

Avalanche Canada mbender, Avalanche Canada

There is distinct variability in avalanche conditions between the north and south of the region. In the north of the region recent heavy loads such as cornice falls have been sporadically triggering full depth avalanches.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

SUNDAY: Mix of sun and cloud / Light south wind / Alpine temperature -3 / Freezing level 1400mMONDAY: Cloudy with scattered flurries / Moderate southwest wind / Alpine temperature -2 / Freezing level 1400mTUESDAY: Mix of sun and cloud / Light to moderate east wind / Alpine temperature 0 / Freezing level 1600m

Avalanche Summary

There have been very limited information sources reporting in the latter half of this week from the north of the region. A Mountain Information Network post from Monday describes a cornice triggered avalanche stepping down to the November deep persistent weak layer or ground in the alpine on a North aspect. Click here to read more details in the post itself. An additional report from Monday indicates a size 2.5 explosives controlled cornice failure stepping down to what was suspected to be a mid-February persistent weak layer in the Duffy Lake area. Yet another report from the same area indicates a size 3 large explosives triggered avalanche stepping down to what was suspected to be a November persistent weak layer. There have been no new avalanche reports from the Coquihalla area or south of the region in the past several days.Recently formed wind slabs are expected to remain reactive to human triggering.

Snowpack Summary

Anywhere from 15-25cm of new snow is sitting on a widespread melt-freeze crust that exists on all aspects and elevations except for high elevation north facing terrain. Recent moderate winds from the south have formed new wind slabs in the alpine and have added load to cornices. On sun exposed slopes and at lower elevations, several crusts likely exist in the upper snowpack which are generally well bonded. Both the mid February persistent weak layers and November deep persistent weak layer seemed to have become reactive to heavy loads (cornice falls and/or large explosives triggers) earlier in the week at upper elevations in the northern part of the region near Duffey and Birkenhead Lakes.

Problems

Wind Slabs

An icon showing Wind Slabs
New wind slabs have recently formed in north facing terrain at higher elevations and are expected to remain reactive to human triggering.
Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

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Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices
Large cornices may become weak with daytime warming or during periods of stormy weather. Recent cornice falls have been triggers for full depth avalanches in the north of the region.
Give cornices a wide berth when travelling on or below ridges.Cornices become weak with daytime heating or solar exposure

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

Elevations: Alpine.

JavaScript chart by amCharts 3.20.8

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Apr 9th, 2017 2:00PM

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