Avalanche Forecast

Issued: Jan 21st, 2018 4:00PM

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

Deryl Kelly, Parks Canada

Jasper.

Two SH layers stand-out in the upper 30-40cms. The reactivity of these layers is highly variable. Look for signs of instability like cracking, whumpfing, and natural activity on similar slopes to help make an informed decision to ride or not.

Summary

Weather Forecast

Light snowfall amounts through to Wednesday perhaps adding another 5-10cm. The winds will continue SW with strong to moderate gusts at RT and will re-distribute any new snow. Alpine temperatures will remain seasonal with alpine highs of -6.

Snowpack Summary

Windslab continues to build in open areas which has covered two troubling surface hoar layers in the top 30 to +50cm of the snowpack. The distribution of this SH in the terrain has been found in immediate lees of wind swept features, around TL elevations and into the alpine. It's potentially active with a light trigger like a unsuspecting rider.

Avalanche Summary

Loose and soft slabs up to size 1.5 reported from steep rocky terrain.

Confidence

Intensity of incoming weather systems is uncertain on Monday

Problems

Wind Slabs

Previous wind events with only light snow has buried two SH layers. New surface windslab sits on the Jan 17 FC/SH. This builds on a now buried windslab over the Jan 7 SH for a total slab size of 20 to 40 cm.

Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.Watch for signs of instability such as whumpfing, or cracking.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

There has been few observations of activity on this layer recently. Suspect this is slower to heal in the alpine.

Be wary of large alpine slopes that did not previously avalanche.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Jan 22nd, 2018 4:00PM