Avalanche Forecast

Issued: Nov 20th, 2019 8:00AM

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

Parks Canada chris gooliaff, Parks Canada

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Today is the first day of the Winter Permit System. Ensure you have a permit to enter the restricted areas, provided they are open today.

A persistent slab has been surprising early season travelers the last few days. Choose conservative lines.

Summary

Weather Forecast

The ridge of high pressure has arrived. Sunny skies today with light N'ly winds and freezing levels rising to 1100m. Thurs brings sun with some clouds, light variable winds, and a weak temp inversion with alpine freezing levels reaching 2000m. Friday will see a mix of sun and clouds, light SW winds, and freezing levels near 1700m.

Snowpack Summary

A 35-50cm persistent slab sits on a crust/surface hoar/stellar layer. Below this are several melt-freeze crusts from late October. Tests are showing easy to moderate results on the persistent slab, indicating they are easily triggered by human loads.

Avalanche Summary

Human-triggered avalanches to size 2 were reported from Balu Pass Monday and the Asulkan Hut area over the weekend. The Balu Pass avalanche buried the person to their neck and gear was lost. Numerous natural avalanches to size 2.5-3 were observed from Tupper, Macdonald, and Cheops during the storm Sunday morning.

Confidence

Due to the number of field observations

Problems

Persistent Slabs

An icon showing Persistent Slabs

The persistent slab sits atop a crust/surface hoar/stellar layer, which is an ideal sliding layer for this avalanche problem. Cool temps will try to lock this slab in, but warm, direct sun may be a strong enough trigger to start an avalanche.

  • Use caution in lee areas. Recent wind loading has created wind slabs.
  • Minimize exposure to steep Southerly slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Nov 21st, 2019 8:00AM