Avalanche Forecast

Issued: Dec 24th, 2013 8:25AM

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 - Timing, track, or intensity of incoming weather system is uncertain on Thursday

Weather Forecast

Wednesday: Mainly cloudy with flurries / Moderate westerly winds / Freezing level at 1100mThursday: Light to moderate (in the south of the region) snowfall / Moderate southwesterly winds / Freezing levels at 1600mFriday: Flurries / Light ridgetop winds / Freezing level at 1200mSpecial Notice: Our radar has just picked-up what appears to be a flying sleigh. Our forecasters believe the sleigh belongs to Santa as it is being pulled by at least 8 reindeer. The sleigh is located in the far north of the province at the 2000m elevation and is currently headed south. More information will be posted as it becomes available.

Avalanche Summary

2 size 1.5 natural slab avalanches were observed in the Duffey Lake area on Monday. The avalanches, which occurred on north/northeast aspects at treeline, are thought to have run on the mid-December surface hoar interface.

Snowpack Summary

Snowpack depths vary greatly across the region with 130cm reported at treeline in the Northern Cascades but only about 50 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.In the south of the region up to 25cm of new snow has fallen. In this area the new snow reportedly saw little wind affect, fell at moderate temperatures, and has most likely gained significant strength. In the north of the region recent accumulations have been modest at best, although moderate to strong winds have shifted new accumulations into relatively small pockets of windslab. 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 very 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

Recent snowfall and southwest winds may have created stiff new windslabs in lee terrain, particularly in the north where winds were reportedly stronger.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

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 25th, 2013 2:00PM