Avalanche Forecast

Issued: Jan 1st, 2020 4:00PM

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

Deryl Kelly, Parks Canada

Jasper.

Strong westerly winds will continue to strip and load lee slopes through the region over the next few days.

Summary

Weather Forecast

The tail end of a Pacific low will continue to bring light precipitation over the next few days. A weak ridge of high pressure is expected on Thursday followed by another low on Friday.Â

CAA's Mountain Weather Forecast for more specific details.

Snowpack Summary

Variable amounts of snowfall through the region, burying large surface hoar, present up to 2200m in sheltered areas. SW winds continue to created new wind slabs on lee features at treeline and above. The bottom of the snowpack consists of very pronounced facets, decomposing crusts and depth hoar.

Avalanche Summary

Concerning results from snowpack tests in Southern forecast region around Mount Wilson. Moderate to hard sudden planar results at treeline on the weak basal depth hoar/facet layers.

Confidence

Problems

Wind Slabs

Most fetch zones are stripped and snow has been redistributed to lee slopes and cross-loaded gulleys. If triggered, the avalanche could awaken weaknesses at the base of the pack creating large avalanches.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Minimize overhead exposure during periods of heavy loading from new snow, wind.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

This weakness could be triggered by large loads or from thin spots in the snowpack. This problem seems more pronounced at treeline where whumphing and cracks have been observed.

Watch for whumpfing, hollow sounds, and shooting cracks.
Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Jan 2nd, 2020 4:00PM