Avalanche Forecast

Issued: Dec 5th, 2013 7:41AM

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

Peter, Avalanche Canada

Kootenay Boundary.

Snowpack information is limited from this region. If you're out in the snow, please send us observations at forecaster@avalanche.ca

Summary

Confidence

Fair - The weather pattern is stable

Weather Forecast

Synopsis: The Arctic ridge of high pressure will continue to dominate the weather pattern through the weekend. Mainly sunny skies and cold temperatures are forecast. Alpine temperatures should hover between -15 to -20. Winds are generally light to moderate from the north, with stronger winds forecast for Sunday.

Avalanche Summary

No reports of natural avalanches releasing after the storm. Storm slab avalanches may continue to be triggered by light additional loads like skiing/riding. Storm slab avalanches that are released may be large and destructive. This storm needs some time to settle and bond, forecast cold temperatures may preserve recently buried weak layers and require more time to settle and bond than when the post storm temperatures are warm. This is a complex avalanche forecasting scenario; complicated by early season timing when we have few observations coming from the field.

Snowpack Summary

A dusting of new snow covers 40-70 cm of previous storm snow. Storm slabs are sitting above recently buried weak layers of surface hoar on North aspects and melt/freeze crusts on solar aspects. In some parts of the region, the storm slab may not be well consolidated and may not result in shears from snow-pit tests. Widespread whumpfing was observed near Nelson from treeline elevations all the way to valley bottom. There are some reports of a deeply buried early season crust that formed in October, this layer is more likely to be found in the high alpine on northerly aspects.Surface facetting continues and new surface hoar growth is likely in some areas. This will be something to watch when the weather pattern finally changes.

Problems

Wind Slabs

Northeast winds have created dense or hard wind slabs in exposed terrain at higher elevations. Watch for cross-loading in gullies and behind terrain features.

Be careful with wind loaded pockets. Be aware of wide variation in snowpack depth>Be cautious as you transition into wind affected terrain.>Avoid travelling in areas that have been reverse loaded by winds.>The best powder will be found in sheltered locations at or below treeline.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

The recent storm snow may continue to be reactive where it sits above surface hoar and/or crusts that were buried at the end of November.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Dec 6th, 2013 2:00PM