Avalanche Forecast

Issued: Dec 2nd, 2011 8:10AM

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

pmarshall, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

A strong ridge of high pressure persists through Monday bringing a mix of sun and cloud, light-moderate N-NW winds, and daytime freezing levels as high as 2500m.

Avalanche Summary

Several thin wind slabs avalanches were reported in the Coquihalla Pass area on Thursday. Although it may be harder to trigger some of the deeper weaknesses in the snowpack, if you do, the resulting avalanche could be very large and destructive.

Snowpack Summary

Strong upper level winds have created wind slabs and scoured areas in exposed terrain, primary on NE-SE aspects. There is a solid rain crust, down 15-30cm below 1800m, which has greatly reduced the likelihood of avalanches at lower elevations. A surface hoar layer has been observed down approximately 45cm in the Duffey Lake area. A facet layer near the base of the snowpack continues to give sudden collapse ("drops") results in snowpack tests. Continued caution is recommended in shallow snowpack areas (lots of rocks or small trees poking through), especially on sun exposed slopes if the sun has any kick, and on any slope that has not recently released.

Problems

Wind Slabs

Watch for hard and soft wind slabs in exposed terrain on a variety of different aspects.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

Weak layers of facets and depth hoar may be lurking deep in the snowpack. Be wary of shallow snowpack areas where triggering deeper weaknesses is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 3rd, 2011 8:00AM