Avalanche Forecast

Issued: Apr 16th, 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, Loose Dry and Cornices.

max darrah, Parks Canada

Jasper.

Travel is good at lower elevation on a widespread and supportive melt freeze crust, and good skiing can be found up high in sheltered Northerly terrain.

Summary

Weather Forecast

Cool temps with good overnight freezes continuing until Thursday, when a warming trend pushes freezing levels up to 2000m. Convective snow showers possible, with the heaviest amounts forecasted for the North Rockies. Winds light westerly.

Snowpack Summary

Windslabs exist on lee aspects of exposed ridgecrests above treeline with a dusting of snow overtop. Buried temperature crusts 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

Several point releases producing loose dry avalanches to size 1.5 on steep, rocky terrain, primarily on solar aspects. Flight in the Chaba and Maligne drainages observed no new slab avalanches or recent cornice failures.

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.

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 - 3

Loose Dry

Numerous loose dry point releases were observed today, mostly from steep and rocky terrain with a solar aspect. These avalanches are triggered by afternoon heating and solar influence.

Avoid travelling under cliffs that are exposed to sluffing from above.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

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.

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

1 - 3

Valid until: Apr 17th, 2013 4:00PM