Avalanche Forecast

Issued: Mar 2nd, 2012 9:33AM

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

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

A warm front is forecast to move over the north coast on Friday night, bringing moderate to heavy precipitation and strong westerly winds. The winds are expected to peak at about 80 km/hr sometime in the early morning. Expect about 5-10 cm of snow overnight and another 5-10 cm during the day on Saturday. The freezing level on Saturday should lower to about 600 metres. Snow is expected to continue on Sunday bringing another 5 cm and strong westerly winds. Temperatures are expected to drop by Monday morning as a ridge of high pressure builds over the region.

Avalanche Summary

Recent avalanche activity consists of new, low density snow sluffing from steep terrain up to size 1.5. On Monday a sled triggered size 2 avalanche occurred in the Telkwa Pass area. Reports indicate the elevation was near 1350 m, on a South aspect. The crown depth was 45 cm, 100 m wide, and ran 100 m down slope. One member of the party was buried up to his chest, but sustained no injuries. A skier triggered size 2 avalanche, also 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. 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

Due to changing winds, wind slabs can be found on N-NE aspects and S-SW aspects in the alpine on exposed slopes at treeline. Currently, up to 60cm of snow sits over the mid February interface. This interface is variable, it consists of a strong melt freeze crust below 1000m, above 1000 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 larger avalanches that occurred earlier this week. This layer should be on your radar, as it may be susceptible to rider triggers. With forecast wind, snow and rising freezing levels this layer may show its wrath again. It's a good time to play conservatively. Below this, the mid and lower snowpack is well settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
New snow and strong westerly winds are developing new windslabs in the alpine and at treeline. Windslabs may fail naturally or be easily triggered with light additional loads.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 6

Persistent Slabs

An icon showing Persistent Slabs
New storm slabs will develop with forecast snow. This adds to the current storm slab instabilities; especially in areas where they overlie buried crusts, facetted snow, and/or sheltered areas with buried surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 6

Valid until: Mar 3rd, 2012 8:00AM

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