Avalanche Forecast

Issued: Nov 27th, 2011 9:00AM

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

Peter, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

Another strong frontal system should reach the area by Monday morning bringing heavy snowfall and strong southwesterly winds. Expect another 25-40cm with this storm. The freezing level should be around 1000-1200m on Monday. Precipitation should taper off on Tuesday as a ridge of high pressure builds in. Mainly sunny skies are expected on Wednesday. The freezing level should be around 500-800m on Tuesday and Wednesday.

Avalanche Summary

Recent reports are limited to the run out zones along the highway corridors near Bear Pass and Terrace. I expect a widespread natural avalanche cycle occurred in many areas on Saturday and into Sunday.

Snowpack Summary

Saturdays system dumped another 50-75cm in many areas. The snowpack depth near treeline is already around 300cm. Fluctuating freezing levels and varying precipitation intensity and wind throughout the recent storms has probably resulted in various weaknesses within upper snowpack. A buried surface hoar layer may be found down close to 100cm, but there is no recent information on the presence and sensitivity of this layer. The mid and lower snowpack is generally well settled and strong with an old rain crust near the ground.

Problems

Wind Slabs

Expect to find deep and dense wind slabs in exposed terrain well below ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 6

Storm Slabs

Weaknesses may exist within or under the recent storm snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Valid until: Nov 28th, 2011 8:00AM