Avalanche Forecast

Issued: Feb 6th, 2012 9:14AM

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

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

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

Weather Forecast

A ridge of high pressure will continue to keep the region dry through Tuesday. Ridgetop winds are light from the SE. Freezing levels near 1000m. The pattern will start to change on Wednesday afternoon. Light snow amounts are expected with freezing levels near 950m. Alpine temperatures could drop to -9, and treeline temps may hover near -3. Weather models seem to be conflicting with precipitation amounts for the outlook. Thursday may bring 2-4mm, accompanied by light NW winds.

Avalanche Summary

No new avalanche observations reported.

Snowpack Summary

Snow surface conditions are variable. Thin, breakable sun crusts are developing on steep solar aspects in the alpine. At treeline and below treeline surface faceting and surface hoar growth (5mm) are forming; especially on shady aspects in sheltered locations. In the Duffy Lake area the upper snowpack continues to settle and bond. Cornice fall is still a concern under the sunny skies and could trigger a large slab avalanche from the slope below. The Coquihalla sees similar surface crusts and crystal forms as the Duffy, but additionally has hard slabs 5-15cm thick due to strong outflow winds. The wind pressed surfaces and hard slabs all sit on a generally well settled upper snowpack. The older storm slab in the Coquihalla is about a meter deep and continues to settle and bond.

Problems

Cornices

An icon showing Cornices
Cornices are likely to be weak in the afternoon due to warm temperatures and strong solar radiation. Cornice falls may release slabs on the slope below.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 6

Wind Slabs

An icon showing Wind Slabs
Strong outflow winds over the past couple days have created hard stiff wind slabs on lee slopes. The y may be stubborn, but could be reactive to rider triggers.

Aspects: North, North East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 7th, 2012 3:00AM