Avalanche Forecast

Issued: Apr 1st, 2012 10:39AM

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

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Monday: light to moderate snowfall - strong southeast winds - freezing level at 1200m Tuesday: light to moderate snowfall - moderate southerly winds - freezing level at 700m Wednesday: light snowfall - strong southwest winds - freezing level at 850m

Avalanche Summary

Natural icefall initiated a small slab avalanche on Saturday. In the north of the region, sluffing was observed in steep terrain in the alpine and at treeline. No other avalanches were reported. We should see an increase in wind slab avalanche activity with forecast weather on Monday.

Snowpack Summary

Light amounts of recently fallen snow overlie previously formed wind slabs. In general, north aspects at higher elevations hold dryer, low density snow while melt/freeze conditions exist on solar aspects in the alpine and all aspects at treeline and below. Solar aspects are becoming moist and unstable under sunny skies. The mid-pack is generally well consolidated; however, the mid February persistent weak layer, comprised of spotty surface hoar, facets and crusts, is buried 80-120 cm below the surface. No recent activity has been reported on this interface. It most likely needs a large trigger on a specific spot. If an avalanche occurs on this weak interface it will be very large and destructive. Below this the snowpack is well settled and strong. Cornices in the area are reported to be very large. Cornice failure could trigger an avalanche on the slope below. On a side note, surface hoar growth has been noted in recent days and should be something to watch as new snow falls.

Problems

Wind Slabs

An icon showing Wind Slabs
Forecast strong winds and new snow will form fresh wind slabs. Watch for triggering in gullies, behind ridge crests and over rolls in terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

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. Use extra caution if the sun shines through.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Apr 2nd, 2012 9:00AM

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