Avalanche Forecast

Issued: Dec 27th, 2014 8:21AM

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

triley, Avalanche Canada

Cariboos.

A persistent weak layer of buried surface hoar is the sliding layer for human triggered avalanches. This problem results in the avalanche danger staying up at Considerable for the forecast period.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

5-10 cm of dry light snow is expected overnight combined with light Northwest winds, alpine temperatures around -12 and freezing levels at valley bottoms. Cloudy with flurries or light snowfall during the day Sunday with accumulations around 3-5 cm. Northeast winds moderate during the day becoming strong Sunday night. Mostly clear with moderate Northeast winds and alpine temperatures near -20 on Monday. Continued cold and clear on Tuesday.

Avalanche Summary

A natural size 3.0 deep persistent slab avalanche was reported that occurred on Friday. The avalanche may have released near the ground (seen from a distance). Skier controlled avalanches were reported up to size 1.5 failing on the mid-December surface hoar layer that is down 30-70 cm.

Snowpack Summary

Some new windslab has formed at higher elevations that is 20-40 cm thick, easy to trigger, and may step down to the mid-December surface hoar. The touchy mid-December surface hoar layer is now buried below a 50-90 cm consolidated slab that developed during last weeks storm. Below 2100 m this slab sits on a thick, solid crust/ surface hoar combination and has been acting as a perfect sliding layer. A hard rain crust with facets from early November is buried over 1 m down and is currently unreactive, however; triggering from shallow rocky and unsupported terrain remains a concern.

Problems

Persistent Slabs

This slab may continue to be triggered by skiers and riders, and may result in long fracture propagations resulting in large avalanches.

Use conservative route selection, dig down and test weak layers before committing.>Stick to simple terrain, small features with limited consequence and be aware of what is above you at all times.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Wind Slabs

New windslabs have developed in the alpine and at treeline that may be easy to trigger.

Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 28th, 2014 2:00PM