Avalanche Forecast

Issued: Dec 10th, 2012 9:13AM

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

pgoddard, Avalanche Canada

South Rockies.

Summary

Confidence

Poor - Due to limited field observations

Weather Forecast

Monday night: Expect winds of up to 70 km/h from the W and light snow overnight. Alpine temp -10.Tuesday: Strong to gale W winds. Alpine temp -10. Light snow. Freezing level 900 m, dropping to surface overnight.Wednesday: Light winds. Alpine temp -9. Freezing level around 1000 m. Light to moderate snow.Thursday: Light to moderate SW winds. Alpine temp -13. Freezing level 400 m. No snow.

Avalanche Summary

Numerous size 1 sluffs and shallow natural wind slabs were observed on Sunday in the southern Elk Valley.

Snowpack Summary

Recent dry snow has been transported by strong NW winds, creating wind slabs in some areas. Loose snow spilling onto fans has created localized loading. A buried rain crust extends to about 1800 -2000 m. A layer of surface hoar buried about 1 m down seems most prevalent on the west side of the region. At the base of the snowpack an early November crust/facet layer remains a concern. Recent tests have shown sudden results at this interface. In general, snowpack observations are sparse in this region and significant variations are likely to exist from one drainage to another. Digging down and making your own observations will be critical to safe slope selection. Any observations from the field are welcome at forecaster@avalanche.ca.

Problems

Deep Persistent Slabs

A release on this early season rain crust could be surprisingly large and destructive.

Avoid shallow snowpack areas where triggering is more likely.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Wind Slabs

Wind slabs are likely to be found on alpine slopes and behind ridges and ribs at treeline and below.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Dec 11th, 2012 2:00PM