Avalanche Forecast

Issued: Dec 12th, 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.

rupert wedgwood, Parks Canada

Jasper.

Warming temperatures and rain on the weekend will increase the avalanche danger at all elevations.

Summary

Weather Forecast

A warm westerly front will pass into the forecast area on friday and saturday with warming temperatures and snow flurries. Highs of +3 in the northerly lower elevation regions of the park with the freezing levels reaching 1,900m. Cooler temperatures can be expected around the Icefields. Strong alpine winds can be expected on Sunday.

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

Patrol on Tuesday observed two avalanches 24 hours old. Size 2-2.5 at 2800m cross-loaded SE to S aspect feature on what appears to be the Oct raincrust 40-50cm down. Suspect solar trigger.

Confidence

Freezing levels are uncertain on Saturday

Problems

Persistent Slabs

The base of the snowpack is weak and facetted. Above this the october rain crust represents a sliding layer. Failures when they occur can step to ground. This has been observed to 2,900m in the past 7 days.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Wind Slabs

Winds from both the south and north over the past 10 days have deposited soft slab conditions in the alpine near ridge tops and open features near treeline.

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 13th, 2013 4:00PM