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Avalanche Forecast

Apr 4th, 2013–Apr 5th, 2013
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
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
1: Low
The avalanche danger rating below treeline will be low

Regions: South Columbia.

Confidence

Fair - Freezing levels are uncertain on Friday

Weather Forecast

Friday: A low pressure system will move over the interior late Thursday through Friday bringing moderate to locally heavy precipitation. Freezing levels will be around 2000m. Winds moderate from the southwest.Saturday: Overcast with light to locally heavy precipitation possible. Winds moderate from the southwest. Freezing level at 2000m.Sunday: A break between off-shore weather systems will bring overcast skies with light amounts of snow and some possible sunny breaks.

Avalanche Summary

Solar aspects have recently been very active showing lots of natural loose wet avalanches and cornice releases up to size 2.5 when the sun has been shining.

Snowpack Summary

At upper elevations 10-15cm of new snow is covering a crust or moist snow. In some places in the alpine and at treeline this new snow may have buried a recently formed layer of surface hoar or facets. At lower elevations (below 2000m) rain has made the snow surface wet or moist.  New snow combined with wind will have made large cornices even bigger.The March 10th surface hoar/crust interface is buried more than 100cm in most places. Although unlikely to trigger, this deep persistent weakness remains a concern because of the potential for very large avalanches particularly with heavy triggers such as cornice falls or lighter triggers on solar aspects where the crust is more prevalent. Below this the snowpack is strong and well settled.

Avalanche Problems

Loose Wet

With little re-freeze overnight, conditions can change rapidly at lower elevations. Avalanche activity, snowballing, moist and wet snow are initial indicators of deterioration and increased hazard.
Avoid travelling on slopes which are becoming wet due to rain, warm temperatures, or sun.>Be alert to conditions that change with elevation.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4

Wind Slabs

New snow combined with wind has created windslabs in the lee of terrain features.
Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4

Cornices

New snow and wind have made large cornices even bigger.
Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 5