Avalanche Forecast

Issued: Apr 6th, 2014 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs and Deep Persistent Slabs.

garth lemke, Parks Canada

Jasper.

Monitor the degree of overnight freezing and severity of daytime heating. A significantly long period of warm temperatures in combination with solar energy can increase the potential for human and natural avalanches particularly on South aspects.

Summary

Weather Forecast

Monday will be some clouds, moderate SW ridgetop winds, and warmer. Freezing levels will be 2000m and slightly higher at Marmot and Maligne. Temperatures should remain in the single plus digits unless the sun is present. Next few days will be cloudy, light dusting of snow with hopefully 10cm Tuesday evening. Temperatures cooling trend Wednesday.

Snowpack Summary

SW winds forming windslab along alpine ridge tops. A temperature crust is found on lower elevation slopes and southerly slopes into the alpine. Windslab developing on this slippery surface should be assessed. Weak basal facets appears to be bridged, requires a large trigger, or a tickle in just the right spot, and would be a large avalanche.

Avalanche Summary

No avalanches reported today. Size 2.5 to ground noted yesterday in Icefields area.

Confidence

Freezing levels are uncertain on Monday

Problems

Wind Slabs

Windslabs have developed along ridgelines and crossloaded features. Their thickness and interface is variable depending on aspect, elevation, and localized weather influences. It may be present on S aspects over slippery sun crust. Evaluate for this.

Use caution in lee areas. Recent wind loading have created wind slabs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

Weak basal facets should be on your radar. It is difficult to predict and would have severe consequences if triggered. Allot of spatial variability exists. Field team reports large tree shaking whumph Sunday, in the trees, E aspect, at 1800m.

Conditions are greatly improved, but be mindful that deep instabilities are still present.Avoid shallow snowpack areas where triggering is more likely.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 7th, 2014 4:00PM