Archived

Avalanche Forecast

Apr 16th, 2013–Apr 17th, 2013

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

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

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Cariboos.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Thursday

Weather Forecast

Wednesday: Light snow. Moderate SW winds. Freezing level near 1500 m. Thursday: Light snow. Light to moderate SW winds. Freezing level near 1800 m. Friday: Moderate snow. Light SW winds. Freezing level near 1800 m.

Avalanche Summary

Several loose avalanches to size 2 were observed on Sunday. A cornice fall also triggered a size 2 avalanche in steep terrain. No avalanches were reported on Monday.

Snowpack Summary

Strong NE winds have created wind slabs at treeline and above on lee slopes, and scoured windward aspects. Cornices in the region are very large and potentially destructive. Some professionals are expressing concern for a surface hoar interface buried within the upper metre or so of the snowpack, mainly on high-elevation northerly aspects. It may be slowly gaining some strength, but these slopes should still be treated with suspicion. On other slopes, recent storm snow overlies a crust. This crust interface has recently become reactive in regions further south.

Avalanche Problems

Wind Slabs

Recent snowfall has been redistributed by strong winds. Wind slabs exist on a variety of aspects at treeline and above. Wind has also formed very large and potentially unstable cornices.

Be cautious as you transition into wind affected terrain.>Travel on ridgetops to avoid wind slabs on slopes below.>Avoid steep slopes below cornices.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4

Persistent Slabs

A weak interface is buried about a metre down. A surface avalanche stepping down, cornice fall, or the weight of a person from a thin-spot trigger point could trigger it.

Choose well supported terrain without convexities.>Be aware of thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 2 - 6