Avalanche Forecast

Issued: Apr 13th, 2012 10:45AM

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.

jlammers, Avalanche Canada

South Columbia.

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 - Freezing levels are uncertain

Weather Forecast

Saturday: light snowfall / light to moderate northwesterly winds / freezing level at 1600m Sunday: a mix of sun and cloud / light westerly winds / freezing level at 1700m Monday: light snowfall / light to moderate westerly winds / freezing level at 1800m

Avalanche Summary

Numerous wet slab and wet loose snow avalanches to size 3 were reported in the region on Thursday, some running full path to ground. They failed at all aspects and elevations bands, and occurred in response to very warm temperatures.Expect ongoing wet snow avalanche activity throughout the weekend, especially at lower elevations,

Snowpack Summary

Very warm temperatures dominated the region throughout the week 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 80cm below the surface, you might find remnants of facetted crystals sitting on a crust in the alpine and at treeline. The mid-February buried surface hoar layer is down about 140-220 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

Forecast light rain and warmer temperatures at lower elevations are very likely to promote ongoing loose wet avalanche activity. Loose wet avalanches can be heavy and entrain mass quickly.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 5

Wet Slabs

There has been ongoing wet slab activity over the last few days with some releases running to ground and/or full path. Watch for glide crack activity as well with forecast rain and warm temperatures at lower elevations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 5

Cornices

Cornices in the region are large and potentially very destructive. A failure could also trigger a large avalanche on the slope below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 6

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