Avalanche Forecast

Issued: Apr 13th, 2012 10:53AM

The alpine rating is moderate, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Loose Wet, Wet Slabs and Cornices.

Avalanche Canada jlammers, Avalanche Canada

Saturday's danger ratings are based on colder conditions in the alpine. If solar radiation is beyond forecast levels, the avalanche danger in the alpine may increase quickly.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Saturday: light snowfall / light to moderate northwesterly winds / freezing level at 1600m Sunday: a mix of sun and cloud / light and variable winds / freezing level at 1700m Monday: light snowfall / light to moderate southwesterly winds / freezing level at 1900m

Avalanche Summary

There was a natural wet avalanche cycle to size 3 on Thursday or Friday that occurred in response to warm temperatures and intermittent solar radiation. I expect ongoing wet snow instabilities throughout the weekend, especially at lower elevations.

Snowpack Summary

Very warm temperatures have dominated the region in recent days and all but the highest, north-facing slopes saw moist to wet surface conditions. As of Thursday morning, slightly cooler temperatures have allowed light amounts of new snow to fall above about 2000m while rain continued to penetrate and weaken the snowpack at lower elevations. Up to 60cm below the surface, you might find a weak crust interface in the alpine and at treeline. The mid-February buried surface hoar layer is down about 200 cm, although avalanches releasing on this layer represent a very low probability-high consequence scenario. Cornices in the region are very large. With spring temperatures, these are more likely to become weak and fail. They could provide a large enough trigger to release deep layers on slopes below.

Problems

Loose Wet

An icon showing Loose Wet
Spring temperatures will promote ongoing loose wet avalanche activity. Loose wet avalanches may be pushy, and can entrain mass very quickly.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Wet Slabs

An icon showing Wet Slabs
Spring temperatures can trigger destructive wet slabs, especially under solar radiation. Warm temperatures can also trigger destructive glide cracks where they exist.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Cornices

An icon showing Cornices
Large cornices exist in alpine terrain. A failure could be destructive by itself, and could also trigger an avalanche on the slope below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Apr 14th, 2012 9:00AM