Avalanche Forecast

Issued: Mar 6th, 2013 9:18AM

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

jlammers, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair

Weather Forecast

Thursday: Clear skies / Light south winds / Freezing level at 600mFriday: Mix of sun and cloud / Light south winds / Freezing level at 900mSaturday: Light snowfall / Light southwest winds / Freezing level at 900m

Avalanche Summary

Recent reports include a few small natural wind slabs in steep lee terrain in response to northerly outflow winds. A few natural cornice failures, ice falls, and glide slab releases have also been reported. One cornice fall observed just north of Terrace triggered a size 3 slab avalanche that is suspected to have released on the late February weak layer. This event could have been a few days old.

Snowpack Summary

Outflow winds (from the north and east) have created new hard and soft wind slabs in exposed lee terrain. In sheltered areas the snow surface consists of facets, surface hoar, or a sun crust/ moist snow on south facing slopes. A layer of surface hoar, facets and/or a crust is buried down 50-90 cm, but most operators report a good bond at this interface. Watch out for cornices, as they are large and fragile. Several large cornice falls have been reported over the past few days. Most have not triggered slabs on the slopes below, however at least one triggered a very large avalanche. The mid snowpack layers are generally well settled and strong. Facets at the base of the snowpack have resurfaced as a concern now that spring is on the doorstep and full-depth releases are becoming more likely (primarily in the northern part of the region).

Problems

Loose Wet

Warm sun is weakening surface snow, particularly on steep south-facing slopes. Loose wet avalanches can entrain a surprising amount of mass as they travel.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

On Tuesday outflow winds produced thin new wind slabs behind terrain breaks, primarily on southwest to northwest aspects.

Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Cornices may fail naturally with daytime warming and sunshine this week. These could potentially trigger a slab on the slope below.

Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 6

Valid until: Mar 7th, 2013 2:00PM