Avalanche Forecast

Issued: Feb 16th, 2014 4:00PM

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

max darrah, Parks Canada

Jasper.

Avalanche control will necessitate intermittent closures along the Icefields Parkway over the next few days. Visit Alberta's Road Report at www.511.alberta.ca for the most up to date info on road closures throughout the week.

Summary

Weather Forecast

10cm by Monday evening, then intensity of precipitation expected to increase through the week with as much as 30-40cm by next weekend. Temps to remain cool and winds predominantly light Southwest with the exception of Sunday overnight when winds will be moderate, gusting strong.

Snowpack Summary

Recent snowfall overlies a layer of small surface hoar and surface facets. A relatively hard mid-pack is providing bridging strength over weak basal facets at tree line and above. Below tree line has a supportive (albeit shallow) mid-pack. Recent wind loading has produced touchy new slabs on Easterly terrain at treeline and above.

Avalanche Summary

Skier accidental yesterday at Marmot basin - size 1.5 on steep Easterly aspect below ridge top at 2100m. This slab was formed by recent loading of the new snow in the past 3 days and slid on the crust/facet interface down 40cm. No natural activity observed on road patrol between Jasper and Saskatchewan crossing yesterday.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Persistent Slabs

Touchy slabs have been found primarily on East facing terrain below ridge crests between 2000 and 2400m. These slabs are sitting on a persistent weak layer of crust and facets and are stiffening up, increasing the likelihood of wide propagations.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Assess start zones carefully and use safe travel techniques.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

New windslabs are forming and adding to the load on lee aspects, primarily East facing terrain. Small windslabs may trigger deeper persistent slabs and increase the consequence of involvement.

Be careful with wind loaded pockets while approaching and climbing ice routes.Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 17th, 2014 4:00PM