Avalanche Forecast

Issued: Feb 15th, 2015 4:27PM

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

steve blagbrough, Parks Canada

Jasper.

http://www.pc.gc.ca/apps/scond/Cond_E.asp?oID=19299&oPark=100092For specific comments on the opening of Whistler and Portal Creek on Monday - go to the snowpack discussion within the forecast details section.

Summary

Weather Forecast

Colder conditions, little in the way of precipitation and light NW winds should do little to change the present avalanche hazard. With all the wild swings in temperature and precipitation types this winter, the snowpack is a complex layer of slabs, crusts, old surface hoar and facets which demands respect from those venturing into the mountains.

Snowpack Summary

Whistler and Portal Creek are open on Monday but tourers should be mindful that this area has seen no ski traffic and only limited field observations. Given the complexity of the snowpack and the occurrence of some very large avalanches, back-country travelers are advised to be conservative in their choice of terrain throughout the forecast area.

Avalanche Summary

There has been a natural avalanche cycle in the last 48 hours with numerous size 2 and 3 slab avalanches at treeline and alpine elevations, many stepping down to the early season basal facets/crust layer. The most notable slide was a full path size 3.5 on the South Churchill Slide path whose crown wall extended for over 800m.

Confidence

Problems

Deep Persistent Slabs

This layer has become more reactive with the recent weather. The weight of skiers, a cornice collapse or surface slides could be enough to trigger these deep and destructive avalanches.

Avoid shallow snowpack areas where triggering is more likely.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Wind Slabs

Moderate to strong westerly winds have led to the development of windslabs on lee and cross loaded features.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 16th, 2015 4:00PM