Avalanche Forecast

Issued: Feb 21st, 2012 9:46AM

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

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Moderate snow amounts Tuesday night into Wednesday morning. Ridgetop winds strong from the NW. A weak ridge of high pressure will bring mainly dry, cool conditions on Thursday. Ridgetop winds 20-30km/hr from the NW. Things will start to ramp up on Friday as a new low arrives off the coast bringing moderate precipitation and strong SW ridgetop winds.

Avalanche Summary

Reports of several natural size 1 soft slabs failing on lee features in alpine terrain. Several skier triggered size 1's have been reported on steeper North aspects near 1900m, crown depths 20cms with good propagation. I suspect there will be an increase in avalanche activity with the forecast wind and snow.

Snowpack Summary

New snow over the past few days have buried a variety of old snow surfaces. These old surfaces are now 30-45cm down and include crusts that exist on all aspects at lower elevations and on steep solar aspects higher up. Facets (sugary snow crystals) and spotty surface hoar (feathery snow crystals) may also exist in combination with crusts, so there may be continued slab reactivity at lower elevations. With more snow and wind in the forecast the new load may have a poor bond to the underlying buried surfaces. The mid and lower snowpack are strong and well settled. The average treeline snowpack depth is about 240cm.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong winds and heavy snowfall will likely create new wind slabs in the alpine, and exposed locations at treeline.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Storm Slabs

An icon showing Storm Slabs
Storm slabs will continue to grow with forecast snow. They may be particulary reactive where they exist in combination with buried crusts.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Valid until: Feb 23rd, 2012 8:00AM