Avalanche Forecast

Issued: Feb 21st, 2019 4:29PM

The alpine rating is moderate, 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.

Windslabs remain the main concern, and will continue to build through the weekend.

Summary

Weather Forecast

Friday: The big news is increasing winds from the West with up to 30cm of snow available for transport. Cool temperatures and flurries through Saturday.Saturday: Winds dying down and switching to Light from the Northeast. Cloudy with flurries, and temperatures dropping throughout the day.Sunday: Cold temps with an inversion, moderate East wind.

Snowpack Summary

10-15cm of new snow has buried previous windslabs on all aspects. The midpack remains strong in deep snowpack areas, but may act as a slab above deep weak layers in shallower areas.

Avalanche Summary

A field trip to Cameron Lake on Thursday found evidence of recent small wind slab and loose dry avalanches in steep rocky terrain at all elevations. An anomalous size 2 slab was also observed below treeline in a steep and shallow snowpack feature that appeared to have failed on a deep weak layer.

Confidence

Due to the number and quality of field observations

Problems

Wind Slabs

Wind slabs will continue to develop with moderate to strong westerly winds on Friday, and moderate Easterly winds on Sunday

Keep an eye out for reverse loading created by N-NE winds.Use caution in lee areas. Recent wind loading has created wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

A layer of weak depth hoar and facets is lurking at the bottom of the snowpack. Recent snow may have been enough to overload this layer in thin snowpack areas.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Feb 24th, 2019 4:00PM