Avalanche Forecast

Issued: Dec 27th, 2013 8:20AM

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

jlammers, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Saturday: Mainly sunny skies / Light winds / Freezing level at 1100mSunday: Overcast skies with no snowfall expected / Moderate west winds / Freezing level at 1100mMonday: Light snowfall / Moderate southwest winds / Freezing level at 1300m

Avalanche Summary

No new avalanches have been reported.

Snowpack Summary

Snowpack depths vary greatly across the region with 130cm reported at treeline in the Northern Cascades but only about 60 cm along the Duffy. In general, the snowpack across the region is significantly thinner than average for this time of year. Terrain below treeline is still mostly below threshold for avalanche activity.At upper elevations steady southwest winds and modest accumulations have formed new wind slabs which may be reactive on steeper, unsupported lee slopes. Below treeline rain has moistened what little snow there is. Previous weak interfaces within the snowpack appear generally well bonded and have been unreactive to recent snowpack tests. The exception to this seems to be in the north of the region where touchy surface hoar buried on December 12th sits about 30cm below the surface. This seems to be the interface to watch as the overlying slab develops. Early season riding hazards such as rocks, stumps and logs are lurking below the surface at treeline elevations and below.

Problems

Wind Slabs

Steady southwest winds, light to moderate accumulations and warmer temperatures are expected to create stiff new wind slabs during the day on Friday. Watch for triggering on steep, unsupported slopes in gullies and in the lee of ridge crests.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be alert to conditions that change with elevation.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Reports from the Duffey area indicate a touchy layer of buried surface hoar now sits under about 30cm of snow. This is likely the layer to watch as the overlying slab develops. -

Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

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