Avalanche Forecast

Issued: Apr 15th, 2013 4:00PM

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

max darrah, Parks Canada

Jasper.

Summary

Weather Forecast

Below seasonal temperatures and minimal precipitation for the next 3 days. Freezing levels remaining low, with winds primarily from the East in the light to moderate range.

Snowpack Summary

Windslabs exist on lee aspects of exposed ridgecrests above treeline with a dusting of snow overtop. Buried temperature crusts exist below 2100m and sun crusts on steep solar aspects at various elevations. Cornices are big and heavy. Some reverse loading of exposed terrain due to moderate North winds in the past few days.

Avalanche Summary

No new avalanches reported in the entire jurisdiction. Several cornice failures occurred last week. A few cornice falls did trigger deep persistent slabs with crowns up to 1m and some initiated wind slabs with a depth of 10-40cm. Observations are supporting a relatively stable snowpack but evaluate each slope as local variations exist.

Confidence

Problems

Wind Slabs

Windslabs can be found on lee aspects in exposed terrain around ridgecrests. Where these slabs sit on previous crusts, the likelihood of a skier triggered avalanche increases.

The recent snow may now be hiding windslabs that were easily visible before the snow fell.Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Cornices

Cornices are large and are a hazard by their sheer mass. They can also trigger deeper layers if failure occurs. Several cornice failures were observed last week - some initiated storm slabs and a few deeper releases.

Extra caution needed around cornices with current conditions.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Apr 16th, 2013 4:00PM