Avalanche Forecast

Issued: Mar 16th, 2013 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Loose Dry.

a.l. horton, Parks Canada

Jasper.

20 cm of snow expected overnight. If more snow falls than expected, the avalanche danger will rise to High in the Alpine.

Summary

Weather Forecast

Heavy snow to begin Saturday night with 20 cm expected. Winds will shift to northerly and will drop to light. Temperatures will fall as the snow begins. The storm will be short lived and be finished sometime before noon on Sunday. By Sunday afternoon the winds will shift back to light westerly, with cool temperatures and light flurries.

Snowpack Summary

Soft slabs have formed immediate below alpine ridgelines from previous moderate to strong West winds. 80+cm of snow has fallen since Wednesday. At treeline, soft slabs are sitting on a thin suncrust that is buried 80 cm deep in wind exposed south facing terrain. Below treeline, 20-30 cm of unconsolidated snow is present over a base of weak facets.

Avalanche Summary

Large natural slab avalanches have run on steep alpine slopes. Several large cornice failures have been observed in the past 48 hrs. At treeline and below, mild temperatures and solar exposure provided the trigger for small loose wet slides south of the Icefields.

Confidence

Forecast snowfall amounts are uncertain on Sunday

Problems

Storm Slabs

Another 20 cm of snow is expected overnight, adding to the 80 cm that has fallen since Wednesday. This new snow will come in with light north winds and rest on previous wind slabs.

The recent snow may now be hiding windslabs that were easily visible before the snow fell.Good day to make conservative terrain choices.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Loose Dry

There will be 20-50 cm of unconsolidated storm snow on and above ice climbs. This snow will be susceptible to solar, wind and human triggering forming loose snow avalanches. Quantities will be large enough to knock climbers off their route.

Avoid travelling on ledges and cliffs where sluffing may have severe consequences.Be cautious of sluffing in steep terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

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