Avalanche Forecast

Issued: Dec 15th, 2018 8:51PM

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

adam greenberg, Parks Canada

Waterton Lakes.

The snowpack in Waterton is extremely variable. Hazard is elevated along the divide where there is potential to step down to deeper layers.

Summary

Weather Forecast

Sunday: Cloudy with flurries and moderate SW winds. Monday: Cloudy with flurries and moderate to strong SW winds. Up to 10cm Sunday night through Monday on the east side of the park.Tuesday: Models are in disagreement, with up to 20cm of snow in western areas of the park accompanied by moderate to strong SW winds and freezing levels rising to 1800m

Snowpack Summary

The snowpack in Waterton is highly variable, but you can count on a weaker structure along the divide where 20-30cm of recent storm snow has formed windslabs on lee (east) slopes which are sitting on a weak snowpack consisting of facets and crusts.

Avalanche Summary

Though there have been few Avalanche observations in the park, our neighbors have been experiencing the first big cycle of the season. Several skier triggered avalanches to size 2 were reported on Alpine and Treeline E-NE slopes, as well as several avalanches from explosive triggers on the October 25 crust to size 2-3.

Confidence

Wind effect is extremely variable

Problems

Wind Slabs

30cm of storm snow since Thursday on the divide along with strong west winds has created windslabs in the alpine and treeline. These are sitting on a weak snowpack and have the potential to step down to deeper layers.

Use caution in lee areas. Wind slabs may step down to deeper layers resulting in large avalanches.Choose ice climbs that are not exposed to avalanches from above.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

The bottom of the snowpack is a combination of crusts and facets that is reactive to large triggers.

Be aware of thin areas that may propogate to deeper instabilites.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Dec 18th, 2018 4:00PM