Avalanche Forecast

Issued: Dec 29th, 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, Persistent Slabs and Deep Persistent Slabs.

deryl kelly, Parks Canada

Jasper.

Icefields Parkway will remain closed overnight Saturday. Check Alberta-511 for details.

Summary

Weather Forecast

New snow totaling 25cm has fallen over the day, tapering off overnight. Sunday, convective flurries are expected to add a further 10-12cm. Strong winds will continue into early next week. A detailed mountain weather forecast is available from Avalanche Canada.

Snowpack Summary

26cm of new storm snow getting transported aggressively by moderate to strong SW winds.

Avalanche Summary

Poor visibility through the Icefields and Wilson areas due to snow and strong winds. Evidence of a large avalanche cycle in the southern end of the bulletin region where snowfall amounts higher than forecasted.

Confidence

Due to the number of field observations

Problems

Wind Slabs

The new snow has come with strong winds at all elevations. Avoid overhead avalanche terrain during periods of heavy loading

Minimize overhead exposure during periods of heavy loading from new snow, wind.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Persistent Slabs

The new snow will fall on to settle snow from last week. Below this the interface with the old snow surface, buried up to a meter deep, is strengthening however, large triggers such as cornices have produced several releases recently.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Avoid thin, rocky or unsupported slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Deep Persistent Slabs

The base of the snowpack is weak and facetted. Likely trigger locations are around rocks, where cold air can penetrate to the base of the snowpack, and shallow snowpack locations.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 3.5

Valid until: Dec 30th, 2018 4:00PM