Avalanche forecast

Banff Yoho Kootenay

Mar 21 – 22, 2022
View on map
Archived · expired 5 years ago

Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable

Highlights

WARMING is expected Tuesday through Wednesday. Expect existing slabs to become more sensitive to triggering.

Avalanche control is planned Tuesday on the Sunshine Ski Area Access Road:

Both the Eagle and Bourgeau Closure Zones are in effect Tuesday.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Last week's slabs are 30-50cm thick but are likely to only be reactive in steep features. Sunday's new slabs are thin, soft and isolated to immediate lees but will be sensitive. Expect all of these slabs to become more reactive with warming.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    Buried crust/facet layers exist in the upper snowpack on solar aspects and all aspects below 1800m. As the slabs overlying all of these crusts becomes heated, they will become much more sensitive to triggering. Wet slab activity may become possible.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    As freezing levels rise expect loose wet sluffs to become active first in lower elevation steep terrain before progressing higher. Depending on solar inputs this may be intensified on steep solar slopes and cliffy terrain.

Weather Forecast

A Pacific system will pass the region well to the north Tuesday, Wednesday. Tuesday the system will produce moderate W to NW winds that will increase to strong as freezing levels approach 2500m under thin cloud. A weak freeze may occur Tues night. Winds shift SW Wed and temps rise further ahead of a cold front Wed arriving Wed evening.

Snowpack Summary

Last week west winds brought 20-50 cm of snow and formed wind slabs in alpine and isolated treeline terrain. These slabs were buried Saturday by 5-15cm that again arrived with gusty W winds that formed small soft wind slabs. On Solar aspects several  buried crusts are found 30 to 80 cm  deep, Temperature crust  up to 1900m is buried 40-50cm deep

Avalanche Summary

No new activity reported Monday. Explosive control in Kootenay Park on Thursday produced unexpectedly large avalanches at low elevations. On Sunday, Bourgeau-Left waterfall (next to Sunshine gondola) released a large natural avalanche that ran over the waterfall and hit Healy Creek. This may have been triggered by a cornice or strong solar effect.

Confidence

Intensity of incoming weather systems is uncertain on Tuesday

Regions covered