Avalanche Forecast

Issued: Dec 18th, 2013 4:00PM

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

mike eder, Parks Canada

Jasper.

While the colder temperatures should reduce natural avalanches, the recent wind slabs developed over the basal facets has the potential to make remote triggering an avalanche in the alpine likely.

Summary

Weather Forecast

Colder temperatures will occur into the weekend with sunny periods on Thursday. Sporadic snow flurries will return for Friday and through the weekend with increasing snowfalls coming early next week. the colder temperatures should lock the snowpack in.

Snowpack Summary

Strong, turbulent winds continue to add to the variable snow distribution at treeline and above. Wind slabs are developing in lee terrain features. These windslabs sit above the October 27 raincrust with weak basal facets at the bottom of the snowpack.

Avalanche Summary

A size 1.5 slab occurred today at 1800m on a slope with a primarily Easterly aspect. This was a thin windslab over basal facets and ran to ground. Colder temperatures should lock the snowpack in for the short term. While there is variable snow distribution on the landscape, there is still potential for slab avalanches to occur in isolated terrain.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Friday

Problems

Wind Slabs

Winds continue to build slabs on the lee aspects near ridgetops and on the lee side of terrain features at treeline and above. Anything line that has enough snow to ski on and is steep enough to slide should be evaluated for wind slabs.

Be cautious as you transition into wind affected terrain.Be careful with wind loaded pockets while approaching and climbing ice routes.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

The persistent slab consists of an October 27 raincrust with facets developing above and below it. It is sporadic in distribution, but even a small avalanche could step down to ground.

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: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Dec 19th, 2013 4:00PM