Avalanche Forecast

Issued: Mar 27th, 2016 4:46PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Storm Slabs and Loose Dry.

Ruari Macfarlane, Parks Canada

Waterton Lakes.

An up-slope storm centered on Waterton will substantially increase both ski quality and avalanche danger. The Danger Levels will depend heavily on how much snow we actually receive. Adjust your decision-making accordingly.

Summary

Weather Forecast

A strong upslope flow develops midday Monday, with snow to valley floor. Expect poor visibility and snowfall, heavy at times, ending midday Tuesday. Amounts differ wildly between forecasts: anywhere from 20 to 100cm in 24 hours, with initially strong NE winds at treeline and alpine elevations. Rising temperatures keep hazard elevated on Wednesday.

Snowpack Summary

Expect new snowfall through Monday & Tuesday to add a substantial amount of storm snow to the upper snowpack. This will bury small Wind Slabs that are difficult to trigger, lee to previous SW winds. These overlie a supportive Melt-Freeze crust which extends into the alpine on all aspects, and caps a strong and consolidated snowpack below.

Avalanche Summary

A widespread cycle of small, Loose Dry avalanches occurred on Friday. On Saturday, forecasters observed shooting cracks from their ski tips, propagating several meters. These cracked 40cm deep through recent wind slabs, isolated to ridgetop lee slopes.

Confidence

Forecast snowfall amounts are uncertain

Problems

Storm Slabs

These will be largest, and most widespread, on S and W aspect lee slopes at Alpine and Treeline elevations. However, new snow may also overload small buried wind slabs that exist near ridges, lee to previous SW winds.

The new snow will require several days to settle and stabilize.Keep an eye out for reverse loading created by an upslope storm.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Loose Dry

Expect natural Loose Dry avalanches from cliffy terrain lee to NE winds during the storm. Human triggered sluffing in more sheltered steep terrain will remain likely throughout the forecast period.

On steep slopes, pull over periodically or cut into a new line to manage sluffing.Avoid travelling under cliffs that are exposed to sluffing from above.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Mar 30th, 2016 4:00PM