Avalanche Forecast

Issued: Dec 16th, 2018 4:00PM

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

jasper snow safety, Parks Canada

Jasper.

We have a very complicated snowpack that requires a thorough assessment before committing to any avalanche terrain. Large whumphs and shooting cracks were noted on Saturday. Ice climbs with overhead hazard should be avoided until the hazard abates.

Summary

Weather Forecast

Monday will be flurries, 8cm of snow, alpine temperature High -5 C and ridge wind southwest 20 km/h gusting to 50 km/h. Tuesday to Wednesday is much the same with potentially 36mm of precipitation from Monday to Wednesday. A detailed mountain weather forecast is available from Avalanche Canada.

Snowpack Summary

New snow on the horizon, following recent storm snow, 60cm since Dec 11th in the Icefields region. New snow has been and will continue to be redistributed by moderate SW winds. This interface, Dec11, overly several weak interfaces such as facets, crusts and isolated surface hoar. The deep persistent weakness still lingers near the ground.

Avalanche Summary

A natural avalanche cycle and subsequent avalanche control work resulted in many slab avalanches up to size 3.5 in the Parkers ridge area on Dec 14th. Saturday's field team toured on Parkers Ridge summer trail (ATES 2) and observed many common signs of instability, like shooting cracks and whumphing.

Confidence

Intensity of incoming weather systems is uncertain on Monday

Problems

Wind Slabs

Moderate SW winds continue building windslabs particularly at ridge-tops. These were sensitive in lee areas, most notably NE, treeline and alpine features.

Minimize overhead exposure during periods of heavy loading from wind.Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1.5 - 3

Storm Slabs

Determining the strength of bond at the Dec11 interface is key to safe travel in open features at treeline and below.

The new snow will require several days to settle and stabilize.Watch for signs of instability such as whumpfing, or cracking.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

The weak Oct25 crust-facet interface is found 20-30cm off the ground. There is serious potential for step-down avalanches if you trigger the wind or storm slab.

Be aware of the potential for wide propagations.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3.5

Valid until: Dec 17th, 2018 4:00PM