Avalanche Forecast

Issued: Nov 28th, 2014 8:54AM

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

pgoddard, Avalanche Canada

Kootenay Boundary.

A Special Public Avalanche Warning is in effect.

Summary

Confidence

Poor - Forecast snowfall amounts are uncertain

Weather Forecast

Very cold arctic air is heading southwards. At the boundary between this cold air and the current warm, moist air, an intense burst of snowfall is anticipated. Friday night: Moderate to heavy snow (10-50 cm), with strong SW winds is possible.Saturday: Light snow may continue through the day. Becoming cold and clear by the end of the day. Light winds.Sunday/Monday: Very cold and dry. Light winds.

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. We had reports of whumpfing and collapsing at treeline in the north of the region.

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

Rapid changes in temperature and wind, coupled with recent snow and/or rain loading, make a complex snowpack. In some areas (especially alpine and northern zones), deep storm slabs may be sitting over a touchy weak layer.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Loose Dry

If the weather forecast holds true, a rapid burst of dry snowfall could quickly build up, causing loose dry avalanche conditions on steep terrain.

Avoid travelling on ledges and cliffs where sluffing may have severe consequences.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Nov 29th, 2014 2:00PM