Avalanche Forecast

Issued: Apr 10th, 2017 3:56PM

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

istorm, Avalanche Canada

South Coast Inland.

Huge variation exists between north and southern parts of the region. Cornices and deep weak layers remain a concern in the north.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

TUESDAY:Â Mix of sun and clouds. No new precipitation. Freezing level near 1800m but Treeline and Alpine temperatures a few degrees above freezing. Light east wind.WEDNESDAY:Â Increasing clouds with possibility of precipitation starting in the afternoon. Accumulations of trace to 10 cm. Treeline temperatures near zero with freezing level near 1500m. Light to moderate east wind.THURSDAY:Â Cloudy with periods of snow. Trace to 10cm or even 15cm of new snow. Treeline and alpine temperatures near or slightly below freezing. Mod southwest wind.

Avalanche Summary

Reports of a few avalanches were received Monday: an couple of accidentally triggered size 1 to 2 storm slabs near Pemberton and Birkenhead. As well as a size 2.5 cornice triggered avalanche near Birkenhead.

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. Previous moderate winds from the south formed wind slabs in the alpine and added load to cornices. Cornices remain but windslabs have likely bonded. 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 remain reactive to heavy loads (cornice falls and/or large explosives triggers) at upper elevations in the northern part of the region near Duffey and Birkenhead Lakes.

Problems

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. Read Avalanche Activity section for more details.

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.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

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.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 11th, 2017 2:00PM