Avalanche Forecast

Issued: Apr 18th, 2013 4:00PM

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

garth lemke, Parks Canada

Jasper.

Daytime warming will increase the probability of cornice failures and avalanches. Ski quality is good with dust on crust. Low elevation crust remaining supportive through the day.

Summary

Weather Forecast

Thursday night may see less of an overnight freeze than previous. Expect light snow next few days and a warm Friday followed by a cooler Saturday. Sunday will be mixed clouds. Monday will be sunny and spring conditions.

Snowpack Summary

Isolated windslabs exist on lee aspects of high elevation ridgecrests with a dusting of snow overtop. Buried temperature crusts below 2100m and sun crusts on steep solar aspects at various elevations. Cornices are big. Overall the snowpack is solid underfoot. Below 1800m the snow is getting thinner and melting fast especially South aspects.

Avalanche Summary

No new avalanches observed today. Visibility was excellent. Generally the area is in a stable trend but investigate each slope individually for isolated windslabs before committing.

Confidence

Problems

Loose Wet

The frequency of moist releases increases with daytime warming and sun particularly on steep solar aspects.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

Isolated pockets of windslab can be found on lee aspects in exposed terrain around ridgecrests. The likelihood of triggering an avalanche increases if it is poorly bonded to temperature crust especially when the day heats up or the sun comes out.

Test slopes before committing to them.

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 a hazard by their sheer mass. They have the potential to trigger deeper layers based on the size of the cornice failure.

Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Apr 19th, 2013 4:00PM