Avalanche Forecast

Issued: Mar 16th, 2012 10:24AM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Persistent Slabs, Wind Slabs and Storm Slabs.

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Saturday

Weather Forecast

Unsettled conditions are expected for Saturday and Sunday. Light winds and convective snow showers are forecast to bring up to 10 cm on Saturday. Clearing overnight should turn to broken skies during the day on Sunday. There may be some clearing on Monday if a ridge of high pressure extends far enough north. If the ridge does not go far enough north, then expect cloud and scattered flurries to move in from the northwest.

Avalanche Summary

Natural avalanches up to size 2.0 and explosive controlled avalanches up to size 2.5 were reported from the Dogtooth on Friday. Avalanches were confined to the 40 cm of new snow. Reports confirm that there was a widespread cycle to size 3.0 in the past 48 hours. A skier remotely triggered a size 3.0 avalanche from about 50 metres away on Wednesday in Canyon Creek. The slide was reported to be from a west aspect below treeline at about 2000 metres. Expect natural and easily triggered avalanches to continue. If the sun comes out, expect natural activity in the storm slab that may step down to the PWL once it is in motion.

Snowpack Summary

40 cm of new snow overnight with light-moderate southerly winds created an unconsolidated slab above the recent storm snow. The combined slab above the mid-february persistent weak layer is now between 150-200 cm. Some operators continue to get easy-moderate sudden planar character shears on the mid-february surface hoar in shallow areas. The persistent weak layer continues to be a concern at all elevations, and may show wide propagations on low angle terrain below treeline. The new snow may consolidate and release naturally if the skies clear and we get some strong solar radiation. Snowpack conditions continue to be tricky to evaluate, and are variable throughout the region.

Problems

Persistent Slabs

An icon showing Persistent Slabs
The deep nature of the mid-February surface hoar layer makes potential avalanches triggered on this layer large and destructive. Regular and ongoing avalanche activity associated with this layer indicates it is very much still alive.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

4 - 8

Wind Slabs

An icon showing Wind Slabs
The new snow arrived with light-moderate winds and settled into a soft slab. Old windslabs may be hidden by the soft new snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Storm Slabs

An icon showing Storm Slabs
Storm slabs continue to build and consolidate. The dense storm slab may be easily triggered by light additional loads. Solar radiation may trigger another round of natural activity.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

2 - 6

Valid until: Mar 17th, 2012 9:00AM

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