Avalanche Forecast

Issued: Dec 22nd, 2014 7:40AM

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

Purcells.

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 (5-20cm) with moderate to strong south-westerly winds and freezing level around 1200m. A cooler northwest flow may bring light snow or flurries on Wednesday and Thursday.

Avalanche Summary

On Sunday, several size 2-2.5 naturally-triggered avalanches were reported. Storm slabs were also triggered by explosives and a skier. Both failed on buried surface hoar.

Snowpack Summary

Anywhere from 20-60cm of recent storm snow overlies a touchy layer of buried surface hoar, which sits on a crust below about 2100m. Winds from the north-west through south-west have created wind slabs, which are very reactive where they overlie the buried surface hoar. A lower layer of surface hoar is also reactive at the northern end of the range, buried down about 40cm. A hard rain crust with facets from early November is buried over 1 m down and is still reactive to light loads in some locations.

Problems

Storm Slabs

Recent new snow has built slabs over a touchy layer of buried surface hoar crystals, creating dangerous avalanche conditions.

Choose well supported terrain without convexities.>Avoid freshly wind loaded features by sticking to ridges and ribs.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

In some parts of the region, large avalanches have been failing on a deeply buried weak layer.

Conditions may be worse in the north of the region, so get to know your local snowpack.>Avoid common trigger zones including thin snowpack areas, near rocky outcrops, and steep alpine slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

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