Avalanche Forecast

Issued: Apr 12th, 2014 4:45PM

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

a.l. horton, Parks Canada

Jasper.

An avalanche cycle is expected Sunday and Monday afternoons as temperatures warm and solar radiation is intense. Travel early and be off slopes before conditions heat up. Expect closures or delays on the Parkway.

Summary

Weather Forecast

Another cold night tonight followed by warming temperatures and sunny skies on Sunday. Sunday night will also be cold but then rebounding Monday with continued sunny skies.

Snowpack Summary

A crust extends from below treeline (TL) to sunny TL aspects. The crust will maintain its strength until it is exposed to prolonged sun and warm temperatures. Wet to moist snow is present below the crust depending on elevation and aspect. Windslabs look thick and ripe on all lee alpine and TL slopes. Cornices are large and looming.

Avalanche Summary

Several loose wet and wet slabs occurred on west aspects below treeline late yesterday afternoon from warm temperatures and solar radiation. Sizes ranged from 0.5 to 2.5.

Confidence

Timing or intensity of solar radiation is uncertain on Sunday

Problems

Wind Slabs

Fat windslabs are present below ridgelines and on cross-loaded features. The bond between these slabs and the snow beneath is uncertain, however, warm temps and solar exposure will weaken them.

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, South.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

Large triggers such as cornice fall or smaller slab/loose wet avalanches may trigger this weakness. Skier could trigger from shallow areas or near rock outcrops.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Loose Wet

A melt freeze crust is present with wet to moist snow beneath. The crust will deteriorate by mid afternoon and and avalanches are likely after this time. Steep solar aspects have the greatest likelihood.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Be very cautious with gully features.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Apr 13th, 2014 4:00PM