Avalanche Forecast

Issued: Jan 23rd, 2019 7:58AM

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.

New windslabs may propagate further than expected on buried suncrust and surface hoar layers.

Summary

Weather Forecast

Thursday: Mainly cloudy with isolated flurries. Moderate west winds. Alpine high -7Friday: Cloudy with sunny periods and isolated flurries. Moderate west winds. Alpine high -7Saturday: Mainly cloudy with isolated flurries. Moderate southwest winds. Freezing level is uncertain with models predicting anywhere between 1500 and 2200m

Snowpack Summary

30cm of recently wind affected snow has gradually loaded either a suncrust below 2000m on solar aspects or spotty surface hoar in sheltered areas between 1600 and 1900m. This may be a problem layer when we see more snow. The midpack is strong in deep snowpack areas, but the facets lingering at the bottom remain a concern in thinner areas.

Avalanche Summary

Skier controlled wind slabs to 1 were reported in the Castle region yesterday.

Confidence

Freezing levels are uncertain on Saturday

Problems

Wind Slabs

Southwest through northwest winds have formed thin wind slabs over a crust / surface hoar layer and may propagate farther than expected. Dig down and investigate the bond of new snow before committing to your line.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

This layer likely requires a large trigger. Be cautious when transitioning from thick to thin snowpack areas

Avoid steep convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 26th, 2019 4:00PM