Avalanche Forecast

Issued: Mar 23rd, 2013 10:01AM

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

pgoddard, Avalanche Canada

South Coast.

Avalanche danger may spike on slopes receiving direct sun. Avoid travelling on or underneath sun-baked terrain.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Sunday-Tuesday: A mix of sun and cloud with light winds. A few flurries are possible on Tuesday. Alpine temperatures near -2, dropping during overnight periods.

Avalanche Summary

Very little activity was reported on Friday. On Thursday, wind slabs were triggered naturally and by skiers in the size 1.5-2 range. Skiers also triggered small storm slabs which failed on a buried crust. On Wednesday, a widespread natural cycle was observed, with avalanches to size 2.5 failing with solar warming. Cornice fall was also occurring.

Snowpack Summary

The snowpack is variable across the region. Recent storm snow has been redistributed by shifting winds into wind slabs over various crust layers in the upper snowpack. On sun-baked slopes, a melt-freeze cycle is in play at the snow surface, leaving a crust behind during overnight cooling, which breaks down by day. Surface hoar, buried down about 50-70 cm, still shows reactivity in snowpack tests, but in general, triggering this layer has become less likely. It still remains possible with a heavy load or from a thin-spot trigger point. Cornices are large and unstable in some areas. Warm temperatures may weaken them further.

Problems

Wind Slabs

Wind slabs may be lurking behind ridges and ribs and in cross-loaded gully features. Cornices may become unstable with mild temperatures and sunny periods.

Travel on ridgetops to avoid wind slabs on slopes below.>Choose well supported terrain without convexities.>Give cornices a wide berth when travelling on or below ridges.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

Avalanches failing on a crust and/or surface hoar layer buried about 50-70 cm down are becoming less likely, but could be triggered with a heavy load, or from a thin or convex-shaped part of a slope.

Be aware of thin areas that may propagate to deeper instabilites.>Choose regroup spots that are out of avalanche terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Mar 24th, 2013 2:00PM