Avalanche Forecast

Issued: Dec 11th, 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.

Early season conditions exist, rocks and downed timber lurk just below the surface.

Summary

Weather Forecast

Cold and unsettled weather over the next 24 hours. Winds will be southerly and light in the valley with up to 10cm of new snow. Towards the weekend the temperatures will warm and significant snow is expected early next week.

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. Recent North winds are loading South aspects.

Avalanche Summary

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

Confidence

Intensity of incoming weather systems is uncertain on Saturday

Problems

Persistent Slabs

Soft slabs exist in wind loaded areas. The failure layer is believed to be a rain crust near the base of the snowpack. Failures on this layer quickly step to ground and have been observed up to 2,800 meters this week.

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

Strong winds near ridge tops have loaded depressions and shallow terrain features with slab snow. Steep and unsupported terrain with terrain traps below are high risk areas.

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 12th, 2013 4:00PM