Avalanche Forecast

Issued: Dec 22nd, 2014 7:28AM

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

pgoddard, Avalanche Canada

South Columbia.

It's easy to trigger avalanches right now. Conditions are expected to deteriorate further before Christmas. Play safe.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Expect moderate snowfall on Tuesday (10-25cm) with moderate to strong south-westerly winds and freezing level around 500m. A cooler northwest flow should bring light snow or flurries on Wednesday and Thursday.

Avalanche Summary

Numerous storm slabs up to size 2.5 were triggered naturally, by skiers (including remote skier triggering) and by explosives on Sunday. Many were on lee east- to north-facing slopes, but there were some reports from all aspects at treeline and above.

Snowpack Summary

Anywhere from 20-90 cm of storm snow has built up and been shifted by winds, creating slabs above a touchy layer of large surface hoar crystals. Below around 2100m, this surface hoar sits on a hard rain crust. Above 2100m the surface hoar sits on well settled and faceted snow. This interface is highly reactive (see avalanche summary). A thick rain crust with facets from early November is buried over 1 m down and may still be reactive in isolated areas.

Problems

Storm Slabs

Slab avalanches have been failing easily with the weight of a person, or even from a distance. Storm snow has built up over a touchy layer of buried surface hoar crystals.

Choose well supported terrain without convexities.>Avoid freshly wind loaded features by sticking to ridges and ribs.>Remote triggering is possible, so give suspect avalanche terrain a wide berth.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

There is still the potential to trigger a deeply buried weak layer, resulting in a surprisingly large avalanche.

Avoid shallow snowpack areas where triggering is more likely.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Dec 23rd, 2014 2:00PM