Avalanche Forecast

Issued: Feb 5th, 2013 9:37AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs and Cornices.

mpeter, Avalanche Canada

Sea To Sky.

Summary

Confidence

Good

Weather Forecast

Wednesday: Expect cloudy skies with moderate snowshowers and strong south/southwesterly winds. Alpine temperatures should reach -6. 25cm is possible.Thursday: Continuing cloudy, with a chance of lingering flurries. Winds should turn more northerly and ease to light values with alpine temperatures reaching -5.Friday: Mixed skies with continued light northerly winds and temperatures around -3.

Avalanche Summary

We have reports of natural, explosive and rider triggered windslabs up to size 1.5 failing on northwest through east facing terrain These are failing at treeline and in the alpine. As the storm snow deepens, expect the activity (size and frequency) to pick up.

Snowpack Summary

Up to 40cm of new snow has fallen, with consistent southerly winds. New windslabs are forming in lee terrain. Newly buried surfaces include old windslabs, temperature and sun crusts and the new snow is bonding reasonably well at this interface. Down a further 20-50 cm sits a persistent interface comprising of crusts, facets and surface hoar crystals. This layer seems to be rounding and bonding under current conditions. The mid pack is generally well settled with the average snowpack depth at treeline around 180 cm.

Problems

Storm Slabs

New windslabs are forming in lee features at treeline and in the alpine due to consistent southwesterly winds. Also, the new snow may initially bond poorly to the crusts present on many slopes; significant sluffing or stormslabbing is possible.

The new snow will require several days to settle and stabilize.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Cornices

Conditions are prime for cornice growth.

Do not travel on slopes that are exposed to cornices overhead.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 6

Valid until: Feb 6th, 2013 2:00PM