Avalanche Forecast

Issued: Feb 28th, 2012 9:20AM

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

Avalanche Canada swerner, Avalanche Canada

The snowpack is tricky to predict at the moment. Backcountry travel requires local knowledge, extensive experience and training. Please read the new Forecaster's Blog Post.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

A continued unsettled weather pattern exists. Wednesday: Light snow amounts 5-10 cm. Ridgetop winds 25km/hr from the East. Treeline temperatures near -10. Thursday: A Pacific frontal system will start to affect the region bringing light snow amounts during the day, and light-moderate amounts later that night. Ridgetop winds will be strong from the West. Treeline temperatures near -8. Friday: Moderate snow amounts. Ridgetop winds moderate from the West. Treeline temperatures near -5. Freezing levels may rise to 600 m, and then drop to valley bottom at night.

Avalanche Summary

A skier triggered size 2 avalanche occurred on Monday in the Smithers/Hankin area. The report indicates the slope was triggered while skiing over a convex feature in an open area within the trees. The skier went for a 20 m ride, and was buried chest deep. No injuries reported. The snowpack is very tricky at the moment. Backcountry travel requires local knowledge, extensive experience and training. The obvious clues that show snowpack instability may not be there. You need to dig deep, do your detective work and make good decisions. Don't let the sunny skies, and other tracks fool you, and/ or lead you into a situation you won't be able to deal with. Rider triggered avalanches are likely. Check out this link to view the incident report database: http://www.avalanche.ca/cac/library/incident-report-database/view

Snowpack Summary

Steady winds are transporting new snow, forming pockets of wind slab up to 70 cm deep on lee features. To compound the wind slab issue, recent winds have been northerly, building reactive slabs on south facing terrain features. Over the past weekend 30 cm of snow fell. This brings a total of 45-60 cm of snow over the mid February interface. This interface is variable and consists of a strong melt freeze crust below 1000m, above 100 m exists facets, surface hoar (in more sheltered areas), sun crust or wind press. The surface hoar is not widespread but is responsible for much of the recent avalanche activity. The mid and lower snowpack is generally well settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
Increasing winds have formed wind slabs on lee slopes and terrain features. Expect to see more widespread loading due to changing winds.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
The new snow has consolidated into a storm slab over the persistent weaknesses. Storm slabs linger as an avalanche problem in areas where they overlie buried crusts, facetted snow, old wind slabs, and/or sheltered areas with buried surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 5

Valid until: Feb 29th, 2012 8:00AM