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Archived

Avalanche Forecast

Mar 5th, 2012–Mar 6th, 2012
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Northwest Inland.

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.

Avalanche Problems

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

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