Avalanche Forecast

Issued: Dec 20th, 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.

garth lemke, Parks Canada

Jasper.

Hazards lurk just below the surface as early season conditions persist. Snowpack depth remains variable across the landscape.

Summary

Weather Forecast

Flurries will occur through weekend with seasonal temperatures ranging from -12 to -20. Temperatures may warm up to -5 on Monday bringing with it 10-15cm and moderate-strong SW winds.

Snowpack Summary

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 sporadically distributed October 27 raincrust with weak facets at the bottom of the snowpack. Colder temperatures are tightening the snowpack but at same time promoting faceting.

Avalanche Summary

Thursday, a size 1.5 slab occurred at 1800m on an Easterly slope. This was a thin windslab over basal facets and ran to ground. Visibility was reduced to valley bottom on Friday.

Confidence

Forecast snowfall amounts are uncertain

Problems

Wind Slabs

Turbulent winds are redistributing snow into sheltered terrain features. Anything that is steep enough to slide and has sufficient snow to ski on should be evaluated for windslabs.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

The Oct 27 raincrust has a sporadic distribution. An avalanche on this layer could still step down to ground and have severe consequences.

Assess start zones carefully and use safe travel techniques.Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Dec 21st, 2013 4:00PM