Avalanche Forecast

Issued: Feb 29th, 2016 6:51PM

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

Ruari Macfarlane, Parks Canada

Waterton Lakes.

We are back to winter conditions for a short spell, heralding heightened avalanche danger. Moderate amounts of new snow will improve skiing, but will be strongly wind affected in exposed terrain.

Summary

Weather Forecast

Cool temperatures on Tuesday morning rise through the day, with SW winds increasing from Moderate to Strong. 5-10cm of snow is forecast for early Wednesday morning. Wednesday and Thursday should see flurries, Freezing Levels from valley floor to 1900m, and Moderate to Strong SW winds.

Snowpack Summary

Crusts and wind affect make for tricky skiing in places, but make for fast travel below treeline. New snow is being blown around by Strong SW winds, developing cornices on ridges, and wind slabs on many lee slopes. A crust-facet combo buried 40-70cm has strengthened somewhat, but has continues to produce sudden test results on some slopes.

Avalanche Summary

Fresh cornices on Forum Ridge on Sunday were reactive to human triggering, but only propagated a few meters. On Monday, a neighboring operation observed a large slab avalanche on a north aspect in the backcountry. It was naturally triggered in extreme terrain by cornice fall.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

Strong SW winds have blown recent snowfall onto lee slopes, forming Wind Slabs. Expect these to grow in size on Tuesday / Wednesday, with more snow and Strong to Extreme winds forecast.

Use caution in lee areas. New snowfall mixed with wind loading is creating Wind Slabs.Test slopes before committing to them.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Cornices have been growing in size. These may fail at any time, although should be given an especially wide berth when temperatures are warm, and/or snow is being transported by wind.

Even small cornice falls may trigger larger avalanches.Minimize overhead exposure to cornices above.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Mar 3rd, 2016 4:00PM