Avalanche Forecast

Issued: Mar 15th, 2013 4:47PM

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

a.l. horton, Parks Canada

Jasper.

Skiing will be great on sheltered low angle treeline slopes. Avoid the temptation to be drawn onto big features until conditions warrant.

Summary

Weather Forecast

Treeline temperatures will remain mild with moderate to strong SW winds continuing Friday night through to Saturday afternoon. Only light precipitation is expected. On Saturday night, winds and temperatures will drop as a moist upper trough will bring another 20 cm or more by Sunday morning.

Snowpack Summary

Soft to hard slabs are forming in the alpine under the influence of moderate to strong Westerly winds. In the Columbia Icefields area over 80cm of snow has fallen Since Wednesday. At treeline, soft slabs exist in the most wind exposed terrain. Lesser amounts of snow fell near Jasper townsite.

Avalanche Summary

Large natural slab avalanches are occurring on steep alpine slopes as moderate to strong SW winds continue to load lee features. Avalanche control on the Icefields Parkway yielded good results with slab avalanches scouring to ground. At treeline, mild temperatures and solar exposure provided the trigger Loose wet slides south of the Icefields.

Confidence

Forecast snowfall amounts are uncertain on Saturday

Problems

Wind Slabs

Thick soft slabs are developing with continued moderate to strong SW winds. Slabs are thickest and most easily triggered just below ridgelines. Slab avalanches can possibly trigger large, full snowpack avalanches on thin snowpack slopes.

Avoid freshly wind loaded features.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Loose Dry

Quantities of loose snow plaster steep cliffy terrain which is often encountered in and around ice climbs. With sufficient volume there currently to produce sizable avalanches, and more on the way, you would do well to avoid this terrain.

Avoid ice climbs that are exposed to steep rocky terrain on solar aspects.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Storm Slabs

More than 80 cm of new snow has fallen in the Icefields area since Wednesday. This snow is settling to form soft slab conditions on sheltered alpine and treeline slopes.

Good day to make conservative terrain choices.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 16th, 2013 4:00PM