Avalanche Forecast

Issued: Apr 4th, 2017 4:17PM

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

Forecast precipitation amounts and freezing levels vary from the north of the region to the south. Higher than forecast precipitation may lead to locally elevated danger ratings.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Wednesday

Weather Forecast

WEDNESDAY: Mix of rain and snow, accumulation Tuesday night into Wednesday 5-15cm / Moderate south wind / Alpine temperature -2 in the north and 2 in the south / Freezing level 1500 m in the north and 1800m in the southTHURSDAY: Mix of rain or snow, accumulation 5-15cm / moderate to strong south wind / Alpine temperature -2 in the north and 3 in the south / Freezing level 1500 m in the north and 1900m in the southFRIDAY: Cloudy with isolated flurries / Light to moderate southwest wind / Alpine temperature 0 / Freezing level 1500m

Avalanche Summary

A 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. 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 was also a social media report from Sunday that describes two skier triggered wind slab avalanches in the Heart Strings area. Click here for details and photos. There have been no new avalanche reports from the Coquihalla area or south of the region in the past several days.On Wednesday, recently formed wind slabs are expected to remain reactive to human triggering. These slabs are expected to be particularly touchy where they overlie a melt-freeze crust.

Snowpack Summary

5-15cm of new snow falling at upper elevations Tuesday night into Wednesday is sitting on a widespread melt-freeze crust on all aspects and elevations except for high elevation north facing terrain. Recent strong 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.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs have recently formed in north facing terrain at higher elevations and are expected to remain reactive to human triggering on Tuesday.
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.

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.
Give cornices a wide berth when travelling on or below ridges.Pay attention to overhead hazards like cornices which could potentially trigger deeper weak layersCornices become weak with daytime heating or solar exposure

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 5th, 2017 2:00PM

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