Avalanche Forecast

Issued: Feb 26th, 2012 9:08AM

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

pgoddard, Avalanche Canada

Cariboos.

Local areas receiving direct sunshine may spike to HIGH danger.

Summary

Confidence

Good

Weather Forecast

Monday: Mainly clear and sunny, with valley cloud. No precipitation. Light westerly winds. Freezing level valley floor. Tuesday/Wednesday: Flurries possible on western slopes. Light-moderate south-westerly winds. Becoming slightly milder.

Avalanche Summary

An avalanche cycle which began on Wednesday has slowed slightly with time, but conditions remain touchy with natural, human and remotely-triggered avalanches in the size 1.5-3 range reported most days. These are running on storm snow weaknesses or on buried weak layers in the upper snowpack. As snowfall and wind-loading ease over the next few days, expect natural avalanches to decrease, but tricky and touchy conditions for human-triggering to continue.

Snowpack Summary

Deep wind slabs exist on many aspects at all elevations. Storm snow totals range from about 60-140cm above the Feb 16. surface hoar layer and the Feb. 9 surface hoar/ crust. The Feb. 9 surface hoar layer is widespread in some areas, while in others it's confined to shady aspects at treeline and in the alpine. A buried melt-freeze crust can be found on solar aspects at all elevations, and on all aspects below about 1600m. Snowpack tests on upper snowpack layers generally give easy to moderate "pops or drops" results. Recent remote and natural triggering further indicates the touchy nature of these weaknesses. Large cornices exist, which could trigger the Jan. 20th facet layer if they fall. Shallow snowpack areas may still harbour basal facets.

Problems

Persistent Slabs

Several weaknesses exist in the upper snowpack, now buried by about 1m of snow. These layers are very sensitive to triggers and pose the threat of large, destructive avalanches which could be triggered by the weight of a person.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 6

Wind Slabs

Wind slabs have grown large on a variety of slopes. Persistent weak layers are buried beneath these slabs, meaning they could be touchy and create very large avalanches. Large cornices also threaten many slopes.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 6

Valid until: Feb 27th, 2012 8:00AM