Avalanche Forecast

Issued: Feb 27th, 2013 10:23AM

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

pgoddard, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Thursday

Weather Forecast

A very wet flow (Pineapple Express) is forecast, but exactly when and where the intense precipitation will occur is a matter of great uncertainty. Thursday-Saturday: Moderate to heavy precipitation. Strong to extreme SW winds. Freezing level around 1600 m, rising for a time to 2000 m.

Avalanche Summary

Numerous skier-triggered slabs have been triggered remotely, propagating across surprising distances and generally surprising people at all elevations. Details of some of these recent incidents can be found here. A natural cycle to size 2.5 occurred on Sunday night and Monday in response to new snow and wind-loading. Expect more avalanche activity over the next few days.

Snowpack Summary

Two very touchy weaknesses of surface hoar and/or a crust within the upper metre or so of the snowpack have already been responsible for a number of avalanche incidents. Add an intense storm, with heavy precipitation rates, warming and very strong winds, and we have a good recipe for widespread avalanche activity. The lower snowpack is well settled.

Problems

Storm Slabs

Storm snow is expected to become very touchy with continuous loading throughout the forecast period, especially where wind-loaded. Storm slabs may step down to persistent weaknesses, creating very large avalanches.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Give cornices a wide berth when travelling on or below ridges.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Persistent Slabs

Persistent weaknesses buried last week demand respect, as they are very touchy, can be triggered from a distance, and are leading to surprisingly large avalanches.

Be aware of the potential for large, deep avalanches due to the presence of persistent weak layers.>Remote triggering is a concern, watch out for adjacent slopes.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 6

Valid until: Feb 28th, 2013 2:00PM