Avalanche Forecast

Issued: Dec 20th, 2014 7:15AM

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

pgoddard, Avalanche Canada

Cariboos.

New snow, strong winds and rising temperatures make a good recipe for rising avalanche danger over the next few days.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Light to locally moderate snow is expected in pulses from Sunday to Tuesday. The heaviest snowfall is expected overnight Saturday/Sunday (5-20cm), accompanied by moderate to strong W to SW winds. Freezing levels are expected to be around 900 m.

Avalanche Summary

No avalanches were reported on Friday, but backcountry travellers may not have had much visibility. It is likely that avalanche activity will follow the trend of the southern neighbouring regions, and we will see storm slabs and wind slabs failing on the buried surface hoar layer. This layer has the potential for remote triggering and wide propagations.

Snowpack Summary

Storm snow and wind slabs are building up. These are expected to bond poorly to a 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. 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

Building storm snow is expected to be shifted by winds into slabs on lee slopes. In more sheltered areas, loose snow avalanches are likely. The new snow sits above a weak layer of buried crystals.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be cautious of sluffing in steep terrain.>Avoid freshly wind loaded features by sticking to ridges and ribs.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

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

Avoid common trigger zones including thin snowpack areas, near rocky outcrops, and steep alpine slopes.>Remote triggering is a concern, watch out for adjacent slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 21st, 2014 2:00PM