Avalanche Forecast

Issued: Nov 18th, 2012 4:00PM

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

garth lemke, Parks Canada

Jasper.

Early season obstacles exist just under the surface. Monday's precipitation, if significant amounts arrive, may be enough to increase the danger rating especially on windloaded slopes.

Summary

Weather Forecast

Series of frontal systems are expected. Strong ridgetop winds and possibly 10-20cm or more of snow with bulk being on Monday evening. A lull in fronts may occur Tuesday before 2nd weaker wave arrives in the evening.

Snowpack Summary

Variable snow distribution in the alpine ranging from 0 - 220cm. There is consistent coverage around 60cm at treeline and below with as low as 20cm in shallow spots. Two midpack crusts are provide surprisingly good skier support. Below treeline snow depths remain at less than critical levels.

Avalanche Summary

No new avalanches have been observed in the last 14 days; however, a healthy input of new snow may overload some weaknesses increasing the potential for avalanche activity. Monitor the incoming storm for amounts and windloading.

Confidence

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

Problems

Persistent Slabs

This layer is present around the Columbia Icefields area from 2200m-2400m. It released with a smooth character between two dense layers. It is a suspect buried surface hoar layer. Other locations it presents as a dense slab over larger crystals.

Avoid unsupported slopes.Avoid convexities or areas with a thin or variable snowpack.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Wind Slabs

This layer was easy to identify 10cm down from the surface. On lee aspects this may sweep a person off their feet.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Nov 19th, 2012 4:00PM