Avalanche Forecast

Issued: Mar 12th, 2017 4:00PM

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

jonas hoke, Parks Canada

Waterton Lakes.

Warming temperatures will increase the sensitivity of weaknesses in the snowpack, be particularly cautious midday - especially if the sun comes out.

Summary

Weather Forecast

Monday: Mainly cloudy. Flurries. Ridgetop winds moderate-strong West. Freezing level 1800m. Alpine temps High -1, Low -5Tuesday: Cloudy. Snowfall (4-6cm). Ridgetop winds light SW. Freezing level 2150m. Alpine temps High -1, Low -3.Wednesday: Mainly sunny. Ridgetop winds moderate-strong SW. Freezing level 2300m. Alpine temps High 0, Low -1

Snowpack Summary

Up to 20cm cm of snow since last week is settling rapidly due to a strong inversion (+4 at 1650m). Moderate SW winds have redistributed the new snow into Storm Slabs. While persistent weak layers in the mid and lower snowpack are relatively strong, near daily snowfall since February 25 means these layers are being increasingly stressed.

Avalanche Summary

Several small-large storm slab, cornice and loose snow avalanches occurred on Saturday as a result of ongoing snowfall, warm temps and wind. On Saturday night a large (size 3) slab avalanche occurred on a cross-loaded NW aspect, this is suspected to have failed on a deep persistent weak layer of facets, possibly combined with a crust.

Confidence

Freezing levels are uncertain

Problems

Storm Slabs

The new snow will require several days to settle and stabilize.Avoid lee and cross-loaded terrain near ridge crests.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Cornices

Pay attention to overhead hazards like cornices which could trigger slabs.Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

Significant snowfall accumulations from the past month are currently stressing the middle and lower snowpack. Persistent weak layers will be further tested as the temperatures rise in to the middle of the week.

Avoid thin, rocky or sparsely-treed slopes.Minimize exposure to big slopes, especially during the heat of the day.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Mar 15th, 2017 4:00PM