Avalanche Forecast

Issued: Mar 7th, 2014 7:36AM

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.

Peter, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair

Weather Forecast

Saturday: Mainly cloudy with periods of light snow and possible sunny breaks around 5 cm. The freezing level is around 1000 m in the north and 1400 m in the south. Winds are moderate to strong from the S-SW. Sunday: Periods of snow 10-15 cm. The freezing level is around 800-1000 m. Winds are moderate to strong from the S-SW. Monday: Mainly cloudy with a chance of flurries. The freezing level is around 800-1000 m. Winds are moderate S-SW.

Avalanche Summary

Some loose dry sluffing was reported in steep terrain on Thursday. This will likely change to slab avalanche activity as the snow piles up and the overlying slab becomes more cohesive with warming temperatures.

Snowpack Summary

Up to 25 cm of new snow (at the time of writing) now sits on a layer of surface hoar or sugary faceted snow on shady slopes, a sun crust on steep solar aspects, or hard wind slabs and scoured slopes in exposed terrain. Initial tests on this new interface showed a poor bond between the new snow and old snow surface. 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 with additional loading from snow and wind or rapid warming. Basal facets and/or depth hoar remain a concern in shallow snowpack areas in the northern part of the region.

Problems

Storm Slabs

The new snow may not bond well to the previous snow surface. Expect deep wind slabs to build in exposed North through East facing terrain at and above treeline, and the potential for wet slab or wet loose avalanches below treeline.

Stick to non-avalanche terrain or small features with limited consequence.>Avoid North-East slopes at or above treeline.>

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.

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

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Mar 8th, 2014 2:00PM