Avalanche Forecast

Issued: Apr 17th, 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, Cornices and Wind Slabs.

garth lemke, Parks Canada

Jasper.

Daytime warming will increase the probability of cornice failures and avalanches. Skiing is good with dust on crust.

Summary

Weather Forecast

Thursday through to Saturday will have scattered flurries and minimal precipitation accumulation. The freezing level should reach 2000m by the afternoon with the possibility of it only going as low as 1600m on Thursday evening. A small pulse of snow is possible Thursday evening. Temperatures will cool Saturday.

Snowpack Summary

Windslabs exist on lee aspects of exposed ridgecrests above treeline with a dusting of snow overtop. There are 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.

Avalanche Summary

Several moist size 2 point releases on solar aspects linked to daytime warming. A couple of semi-recent large cornice drops with no avalanches initiated below have been observed.

Confidence

Problems

Loose Wet

The frequency of moist point 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

Cornices

Cornices are large and a hazard by their sheer mass. They have the potential to trigger deeper layers.

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

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 especially as 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

Valid until: Apr 18th, 2013 4:00PM