Banff Yoho & Kootenay National Park Avalanche Forecast

Issued: Nov 16th, 2021 4:00PM

Tue Nov 16th Current Conditions
Alpine Considerable Treeline Moderate Below Treeline Low
Wed Nov 17th 2 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Low
Thu Nov 18th 3 Day Outlook
Alpine Moderate Treeline Low Below Treeline Low

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Storm Slabs and Loose Dry.

Although the storm has passed and the temperatures have cooled, large avalanches were directly observed today. The storm snow needs more time to settle and bond.

Summary

Weather Forecast

Cooler temperatures are expected over the next few days with valley temps staying below zero. Minimal precip associated with a benign weather pattern is expected. The wind could be the most intense input with wind speed well in to strongĀ  range from the West on Thursday.

Snowpack Summary

Up to 80cm of storm snow since Friday with moderate SW winds have created windslabs in the alpine and at treeline and storm slabs at all elevations. This buries a relatively thin, facetted snowpack with a couple crusts in it. Total snow depths are 60-100cm at treeline with more in the alpine. Below 2000m, rain has saturated the snowpack.

Avalanche Summary

Forecasters observed the remnants of the cycle that ended with the cooling of temperatures this morning. Storms slabs up to size 3.5 were observed throughout Banff, Yoho and Kootenay highway corridors. Today, Lake Louise reported triggering a size 3 avalanche 250m wide on the Nov 5th crust using explosives.

Confidence

Due to the number and quality of field observations

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely - Possible

Expected Size

1 - 2.5

Conditions from the recent storm have formed wind slabs, predominantly in the alpine, but also in some treeline areas. These will take a few more days to heal following the first major storm of the winter.

  • Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.
  • Use caution in lee areas. Recent wind loading have created wind slabs.

Aspects:

North, North East, East, South East.

Elevations:

Alpine, Treeline.

Storm Slabs

An icon showing Storm Slabs

Likelihood

Possible

Expected Size

1 - 2

The recent storm cycle has created widespread storm slabs. This problem still needs time to settle and bond, so treat steep open slopes at treeline and in the alpine as suspect.

  • Make observations and assess conditions continually as you travel.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Loose Dry

An icon showing Loose Dry

Likelihood

Possible

Expected Size

1 - 2

Up to 70 cm of recent storm snow is available to run as loose dry avalanches from steep terrain. Watch out for increased sluffing if the wind picks up or changes direction.

  • Be careful of loose dry sluffing in steep, confined or exposed terrain.

Aspects:

All aspects.

Elevations:

Alpine.

Valid until: Nov 17th, 2021 4:00PM

Forecast Trend

The latest forecast danger ratings, broken down to elevation. See how an elevation is trending.