Avalanche Forecast

Issued: Dec 13th, 2013 4:00PM

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

mike eder, Parks Canada

Jasper.

A size 2 avalanche occurred yesterday on the middle pitches of a popular ice climb indicating that slabs are loaded in gully features. Pay attention when moving between pitches on ice climbs.

Summary

Weather Forecast

A front will be coming through sometime between Friday night and Sunday morning with strong Westerly winds and snow flurries. Warmer temperatures are expected in valley bottoms and may be acompanied by some rain. Snow flurries may accumulate to between 10 -20cm for the weekend, while the valley bottoms will see only dustings.

Snowpack Summary

Variable wind slab on lee features at treeline and alpine elevations. Variable snowpack depths, particularly in the alpine, with pockets up to 1m deep. October's rain crust is sporadically distributed but forecasters are still investigating this condition. Last weeks North winds have loaded slab snow onto South aspects.

Avalanche Summary

Friday's patrol on Highway 93 resulted in no new avalanches observed. However a report from climbers indicated a size 2 slab release on Thursday morning on the middle pitches of polar circus which is a popular ice climb in the area. Strong wind gusts were evident on the climb at the time of the slide indicating snow loading in the gully.

Confidence

Timing of incoming weather systems is uncertain on Saturday

Problems

Persistent Slabs

Wind loaded terrain features with enough snow to ski on may have this weakness in the snowpack.

Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.Be careful with wind loaded pockets while approaching and climbing ice routes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Wind Slabs

Last week's Northerly winds may have developed slabs in unexpected locations on south aspects and terrain features. Evaluate the slope for where a small slide might sweep you down into rocky terrain.

Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 14th, 2013 4:00PM