Avalanche Forecast

Issued: Nov 28th, 2011 9:41AM

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.

ghelgeson, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

25 cm to 70 cm expected from 4pm Mon - 4pm Tue.

Avalanche Summary

Control work in the North on Bear Pass on Sunday produced numerous dry loose snow avalanches size 1 -2, 15-30 cm in depth on SW - S aspects. One Xh size 2.5: 50 w x 1200 L x 100-150cm depth. To the South, Shames reported a Na SL sz 3.0, E @1300 m. 250 w x 1700 long. Failing on Nov11-19 SH. Other control work produced results very similar to that in the North.

Snowpack Summary

Saturdays system dumped another 50-75cm in many areas. Sunday brought another 25 - 35cm to upper elevations. 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 100/150cm, but there is no recent information on the presence and sensitivity of this layer. The mid and lower snowpack is generally well settled/strong with an old rain crust near the ground.

Problems

Wind Slabs

New snow combined with strong winds have created dense wind slabs at and well below ridge top. Additional wind and snow will further exacerbate this problem.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Storm Slabs

Weaknesses may exist within storm snow; 25 - 150 cm in depth.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Valid until: Nov 29th, 2011 8:00AM