Avalanche Forecast

Issued: Mar 6th, 2014 7:38AM

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

Peter, Avalanche Canada

Northwest Coastal.

Temperatures are forecast to rise through the day on Friday, peaking on Friday night and Saturday. If it warms up earlier and snow turns to rain expect higher avalanche hazard than posted for Friday.

Summary

Confidence

Fair

Weather Forecast

Friday: Moderate to heavy snowfall – 20-40 cm (heaviest along the coast). The freezing level climbs to 1400 m in the south and 500 m in the north. Winds are crankin’ from the S-SW. Saturday: Moderate snowfall – 10-20 cm. The freezing level is between 1000 in the north and 1300 m in the south. Winds are moderate to strong from the S-SW. Sunday: Periods of snow. The freezing level is around 1400 m lowering throughout the day. Winds are moderate to strong from the S-SW.

Avalanche Summary

There are no new reports of avalanches from Wednesday. There's finally a weather change on the horizon! Expect conditions to start changing quickly on Friday and through the weekend.

Snowpack Summary

Persistent strong outflow winds (from the northeast-southeast) have scoured windward slopes and created hard or dense wind slabs in exposed lee and cross-loaded terrain. Cold clear weather has also promoted surface hoar growth and surface faceting on shady slopes and a sun crust on steep solar aspects. The mid February weak layer of surface hoar or a crust/facet combo is buried 30-90 cm deep. There has been no reported activity on this layer recently, but watch for it to wake up when the weather pattern shifts to moist and mild heading into the weekend. Basal facets and/or depth hoar remain a concern in shallow snowpack areas in the northern part of the region.

Problems

Wind Slabs

Expect deep and dense new wind slabs to form in exposed north to east facing terrain at all elevations. The new snow will also hide old hard wind slabs from the recent easterly outflow winds.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

New loading from snow and wind, combined with significant warming, may be enough to wake up the mid February persistent weak layer and create very large avalanches.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Whumpfing is direct evidence of a buried instability.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 7th, 2014 2:00PM