Avalanche Forecast

Issued: Apr 14th, 2012 10:38AM

The alpine rating is considerable, 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

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Ridging will bring mostly clear conditions to the region on Sunday with light westerly winds and freezing levels at about 1700m. Light precipitation will commence late Monday intensifying slightly overnight and continuing Tuesday. Winds will be moderate /southwesterly on Monday, switching to light/northwesterly by Tuesday. Freezing levels are expected to increase to 1900m on Monday dropping back to 1700m by Tuesday. Confidence: Good for Sunday, fair for Monday/Tuesday.

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 or when solar radiation is strong.

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. Since 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 and solar radiation will promote ongoing loose wet avalanche activity. Loose wet avalanches may be pushy, and can entrain mass very quickly.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 5

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: All elevations.

Likelihood

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 - Likely

Expected Size

1 - 6

Valid until: Apr 15th, 2012 9:00AM