Avalanche Forecast

Issued: Dec 1st, 2021 4:00PM

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

Timothy Johnson,

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Maligne Lake Road and the Icefields Parkways are both currently closed. The Icefields Parkway could open from Jasper to Parker Ridge late Thursday morning. Check Alberta 511 for updates. This new snow will take time to settle so keep it conservative.

Summary

Weather Forecast

Thursday: A mix of sun and cloud.

Alpine temperature: High -9 C.

Ridge wind west: 20 km/h gusting to 50 km/h.

Freezing level at valley bottom.

Friday: Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -16 C, High -13 C.

Mostly light ridge wind occasionally gusting to 35 km/h.

Freezing level at valley bottom.

Snowpack Summary

About 30 cm of storm snow fell in the last 24hrs in the Parker Ridge area. About 20cm of new snow around Maligne Lake. Freezing level is about 2100m with the snow line around 1200m. The mid-pack is around 80cm thick above a thin crust near the ground in some locations. Snowpack is shrinking rapidly at lower elevations.

Avalanche Summary

Multiple, natural wet loose avalanches up to Size 2 observed on the Icefields Parkway early in the storm. We can expect more have run since the storm started.

Confidence

Due to the number and quality of field observations

Problems

Storm Slabs

An icon showing Storm Slabs

We can expect storm slabs in the trees and in non wind affected tree line locations. In the alpine with strong SW winds we can expect wind slabs to be forming.

  • Avoid avalanche terrain during periods of heavy loading from new snow and wind.
  • If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The average 1 meter snowpack has a crust near the ground surrounded by weakening large grain facets. This is a layer to watch as our neighbors are experiencing activity on it.

  • Avoid thin rocky or unsupported terrain features.
  • Use caution on open slopes and convex rolls

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Valid until: Dec 2nd, 2021 4:00PM