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Archived

Avalanche Forecast

Apr 21st, 2012–Apr 22nd, 2012
Alpine
Below Threshold
The avalanche danger rating in the alpine will be below threshold
Treeline
Below Threshold
The avalanche danger rating at treeline will be below threshold
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold
Alpine
Below Threshold
The avalanche danger rating in the alpine will be below threshold
Treeline
Below Threshold
The avalanche danger rating at treeline will be below threshold
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold
Alpine
Below Threshold
The avalanche danger rating in the alpine will be below threshold
Treeline
Below Threshold
The avalanche danger rating at treeline will be below threshold
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold

Regions: South Coast.

Daily bulletins with danger ratings are finished for the season for this region. General advice can be found in the Avalanche Problems section and on the Forecast Details tab below. Additional information can be found in the Forecaster Blog.

Weather Forecast

Avalanche Summary

Spring conditions exist in the region. Avalanches are most likely to occur in response to solar radiation, warm temperatures, and periods of rain. Particularly dangerous conditions may develop during prolonged periods of warming, heavy rain, or on days with no overnight freeze. Under these conditions, surface avalanches may step down and trigger deeper wet slab avalanches. Prolonged warming may also weaken large and destructive cornices, which are a danger in themselves or could act as a heavy trigger on the slope below. Typically, avalanche activity ramps up during the day and is at a peak during the afternoon. If it's raining or there was no overnight freeze, avalanche activity can happen at any time.

Snowpack Summary

As we transition into spring, the surface layers have a great deal of influence on the snowpack. When there is a solid re-frozen surface crust, travel is fast and easy, and the snowpack is held together by the surface cap. Any deeper persistent weak layers are unlikely to fail until the surface cap breaks down from daytime heating. During warm conditions, melt water is able to percolate within the snowpack and cause surface layers and any deeper weak layers to fail. If it cools off and snows, new snow may not bond well to the hard spring crusts, and isolated storm and wind slabs can easily develop.

Avalanche Problems

Loose Wet

Loose wet avalanches are most likely on steep slopes when temperatures are warm, e.g. on slopes receiving sunshine, during rainfall, in the afternoon and at low elevations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1 - 4

Wet Slabs

Prolonged warming may weaken deeper layers and cause wet slab avalanches. Avoid exposure to slopes which have glide cracks.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 6