Avalanche Forecast

Issued: Jan 20th, 2014 4:00PM

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

garth lemke, Parks Canada

Jasper.

Still not the time to ski big lines despite Moderate rating. Lots of variability across the landscape with a lurking basal weakness. Shallow locations are the likely trigger spots. Human triggered avalanches are possible on specific terrain features.

Summary

Weather Forecast

Mostly dry the next few days with possibly very light snow Tuesday and Wednesday. Temperatures will range from -3Â°C in the afternoons to -12Â°C at night. Light winds from the WSW on Mon night into Tuesday diminishing to calm by Wed morning.

Snowpack Summary

Snowpack below treeline is 85cm deep, low density snow with a 20-40cm stiffer midpack over weak basal facets. It remains the weakest of our elevation bands as not much bridges the basal facets. Above TL, snowpack ranges from 10 to 130cm where a thicker midpack bridges the basal facets. Variable wind slabs present with the previous aggressive winds.

Avalanche Summary

Natural activity has tapered off. Thursday's control work on the Icefields Parkway yielded large avalanches to size 3 on all alpine aspects releasing on either the storm snow interface or on basal facets.

Confidence

Problems

Deep Persistent Slabs

The basal facets are weaker below tree line. Where the snow is deeper at higher elevations, the mid-pack bridges the weak basal facets; however, snowpack depth varies so much that its hard to inspire confidence in stability.

Be aware of thin areas that may propogate to deeper instabilites.Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Wind Slabs

Wind slabs of variable thickness and hardness dot the landscape. Many windpressed and stripped features will be encountered once you leave the shelter of the trees. Triggering this could dig down to the basal facets increasing the consequence.

Avoid cross loaded features.Be aware of the potential for wide propagations due to the presence of hard windslabs.

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

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Jan 21st, 2014 4:00PM