Avalanche Forecast

Issued: Feb 12th, 2023 4:00PM

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

Avalanche Canada CG, Avalanche Canada

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Strong winds and overnight snow will promote storm slab formation Monday morning.

Natural avalanche activity is likely Sunday night through Monday.

Summary

Confidence

Moderate

Avalanche Summary

Several sz 2-3 natural avalanches were reported from the backcountry Saturday.

Cheops North 4 had a loose avalanche step down to the storm slab interface lower in the path.

A sz 2.5 cornice failure off Mt Bonney scrubbed the face below down to glacier ice.

Snowpack Summary

This past week's 60cm of storm snow and strong SW winds have formed several potential failure planes in the upper snowpack, especially in wind exposed areas.

The mid-snowpack consists of generally well bonded, rounded grains.

The Nov 17 deep persistent weak layer, composed of large facets and in some locations a decomposing crust, has been dormant in GNP for several weeks now.

Weather Summary

A vigorous frontal system plows through Rogers Pass Sunday night, bringing strong winds, snow, and mild temps.

Tonight: snow, 20cm, Alp low -8*C, mod/gusting strong SW winds, 800m FZL

Mon: convective flurries, trace to 5cm, Alp high -8*C, light/gusting moderate W winds, 1000m FZL

Tues: mix of sun/cloud, Alp high -10*C, light NW winds

Terrain and Travel Advice

  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • Avoid exposure to slopes that have cornices overhead.

Problems

Storm Slabs

An icon showing Storm Slabs

Incoming snow with strong SW winds will rapidly build reactive storm slabs in Alpine and Treeline lee features. The peak of the system will hit in the middle of the night, but expect sensitive surface slabs Monday morning.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Feb 13th, 2023 4:00PM

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