Avalanche Forecast

Issued: Jan 6th, 2014 9:03AM

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

Avalanche Canada slemieux, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

Tonight and Tuesday: A slight chance of precipitation with a weak upper disturbance passing through the region late Tuesday. NW winds becoming lighter in the afternoon with freezing levels at the surface.Wednesday: Another system is tracking through the region which should leave light to moderate precipitations. Winds should pick up again and blow from the W moderately. Freezing levels rising slightly to reach around 800 m of elevation. Thursday: Similar situation for Thursday as a more zonal flow is allowing frontal systems to move across BC. Precipitation amounts are still not certain but they look a little bit less than the previous system.

Avalanche Summary

No new natural avalanches were reported. NorthWest of Nelson area, a skier triggered a size 1.5 on a N aspect which would have a run on a surface hoar layer down 25 cm. In the same area, a size 2 was also triggered by a heavy load on a SE aspect which would have initiated in a crossloaded feature and would have run on deep basal facets.

Snowpack Summary

A SW wind event created touchy windslabs on lee slopes and on crossloaded features in the alpine and at treeline. These windslabs are quite thick near ridge top and will still be touchy. Storm snow is settling but beware of the possibility of sluffing in steep shady terrain. A surface crust exists on steep S aspects below treeline.  Persistent weak layers (PWL) are still a concern to avalanche professionals. Multiple surface hoar layers located down 25cm, 40 cm and 90 cm are giving variable snowtest results and the facet/crust layer down 100 cm has given multiple sudden planar snowpack test results mostly on S aspects. The surface hoar layer down 90 cm would be more sensitive on N and NE aspects and the facet/crust layer would be more sensitive on S aspects. There is quite a variability throughout the region regarding the persistent weak layers. The Eastern half of the region area seems to be the most problematic.

Problems

Wind Slabs

An icon showing Wind Slabs
Windslabs located under ridgetops mostly on NE and E facing slopes will be sensitive to skier triggering. 
Use ridges or ribs to avoid pockets of wind loaded snow.>Travel on ridgetops to avoid wind slabs on slopes below.>Dig down to find and test weak layers before committing to a line.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Jan 7th, 2014 2:00PM

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