Avalanche Forecast

Issued: Dec 23rd, 2013 8:37AM

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

Sea To Sky.

Summary

Confidence

Fair - Wind effect is extremely variable

Weather Forecast

Tuesday: Mainly cloudy / Light southwest winds / Freezing level at 700mWednesday: Flurries / Moderate southwest winds (with extreme gusts) / Freezing level at 1000mThursday: Light snowfall / Moderate southwest winds / Freezing level at 1600m

Avalanche Summary

No avalanche activity had been reported at the time of publishing.

Snowpack Summary

New snowfall amounts have been highly variable throughout the region with southern areas receiving as much as 25cm throughout Sunday. Strong southwest winds have created pockets of touchy wind slab in exposed lee terrain and cross-loaded features, and scoured windward slopes. Roughly 20-45cm below the surface you may find a variety of old surfaces which formed during the early December cold snap. These surfaces include sugary faceted snow (which may overlie a crust in some areas), spotty surface hoar in sheltered terrain, and hard wind slab on south-facing alpine terrain. In most places the more recent snow seems to be well bonded to this interface, but touchy instabilities have been reported from the Callaghan/Tricouni area.Snowpack depths vary greatly across the region, but are significantly lower than average for this time of year. Terrain below treeline is still mostly below threshold for avalanche activity. Early season riding hazards such as rocks, stumps and logs are lurking below the surface in many areas. In glaciated terrain new snow on the surface might be just enough to hide open crevasses where supportive snow bridges have not yet developed.

Problems

Wind Slabs

Recent snowfall and strong southwest winds will have created stiff new windslabs in lee terrain. Although they may be gaining strength, they may propagate over wide distances, particularly in the south where recent accumulations were significant.

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

Expected Size

1 - 3

Persistent Slabs

Weak crystals overlying a crust have been reported from the south of the region. This spotty yet reactive interface is buried up to about 50cm below the surface and may have serious potential to catch riders by surprise.

Dig down to find and test weak layers before committing to a line.>Make observations and assess conditions continually as you travel.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

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