Archived

Avalanche Forecast

Mar 12th, 2017–Mar 15th, 2017

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Waterton Lakes.

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

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

Avalanche 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