Avalanche Forecast

Issued: Mar 5th, 2012 9:45AM

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.

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Wednesday

Weather Forecast

Clear skies and cold temperatures are forecast for Monday night. Cloud should start to build during the morning as the wind veers to the west and increases to moderate. Expect about 2-5 cm of snow Tuesday afternoon and another 5 cm by Wednesday morning. Wednesday is expected to be unsettled with flurries, moderate winds, and rising freezing levels. A warm front should move in from the Pacific on Thursday bringing strong southerly winds, high freezing levels, and heavy precipitation.

Avalanche Summary

We have a report of a natural size 2.5 on a North aspect in "Big Simpsons Gulch" that ran from the crater lake ridge and triggered a size 2.0 on a ESE aspect lower down and then triggered a size 2.0 slab below the big cliffs. We are not sure how old this avalanche is, and believe that it was the result of a cornice fall.

Snowpack Summary

Moderate southwest winds transported the 3-5 cm of new snow that we have received over the past two days into thin new windslabs at ridgetops. 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.

Problems

Wind Slabs

An icon showing Wind Slabs
Thin windslabs may take a couple of days to settle and bond.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
The persistent weak layer continues to be buried by a few cm each day. Avalanches on this layer have not been reported for a few days, but we feel that it could still be easily triggered by skiers and riders.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 6th, 2012 8:00AM

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