Avalanche Forecast

Issued: Nov 27th, 2014 8:26AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Loose Wet.

pgoddard, Avalanche Canada

Kootenay Boundary.

A Special Public Avalanche Warning is in effect. There seems to be a lot of variability in the snowpack across this region. Conditions are expected to be worse in the north.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

The current warm stormy flow is expected to be replaced by brutally cold arctic air this weekend.Friday: 10-25 mm precipitation. Temperatures are generally remaining warm, with a freezing level near 1900 m. Rapid cooling late in the day, which may lead to snow to low levels, and deep dry new snow at upper elevations. Strong to gale SW winds, easing as the cold air/snow arrives.Saturday: Any remaining snowfall should end by afternoon. Becoming cold and clear. Light winds.Sunday: Cold and clear. Light winds. Brrr.

Avalanche Summary

A widespread loose wet and wet slab avalanche cycle to size 2 was observed on Thursday at treeline and below in the south of the region. No observations were made in the alpine.

Snowpack Summary

Around Kootenay Pass, rain moistened (and weakened) the snowpack to perhaps about 2000m on Thursday. It's expected that the snowpack in this region may remain weak through the warm part of Friday, but strengthen rather quickly after the cold snap arrives.In the Whitewater backcountry, a weak and shallow snowpack was reported on Wednesday, with lots of whumpfing and collapsing. Due to a lack of field observations, it is unclear how Thursday's warm temperatures/ rain have influenced the snowpack here. Above about 2000m and in the north of the region, I have the most avalanche concerns. It's these areas which may be harbouring a weak layer (formed during November's dry spell), now overloaded with storm snow. We have very limited field information. If you have been out in the mountains, we'd love to hear from you. Please email us at forecaster@avalanche.ca.

Problems

Storm Slabs

At high elevations, especially in the north of the region, new storm slabs may overlie a reactive weak layer.

Choose regroup spots that are out of avalanche terrain.>Ride slopes one at a time and spot for your partners from safe locations.>Avoid freshly wind loaded features.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Loose Wet

Loose wet snow may continue to be weak in the morning, but this problem will quickly decrease when the cold arctic air arrives.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Nov 28th, 2014 2:00PM