Avalanche Forecast

Issued: Nov 25th, 2020 8:07AM

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

Chris Gooliaff,

It dumped last night! 30cm in the alpine will freshen things up, but winds will create reactive soft slabs.

Use caution in the lee of alpine and tree-line features. These surface slabs could provide enough mass to trigger the deeper persistent slab.

Summary

Weather Forecast

Unsettled in the wake of yesterday's cold front, expect flurries with gusty winds.

Wed: Isolated flurries with trace amounts, mod W winds, Alp high -9*C

Thurs: Isolated flurries,-9*C, mod SW winds

Fri: Flurries, 5cm, mod/strong SW winds, Alp high -3*C

Snowpack Summary

30cm overnight with SW'ly winds increasing in the last few hours will be forming storm slabs in alpine lee and exposed features. The Nov 5th crust complex (3-10cm thick) is now buried over 1m deep and can be found up to 2500m on all aspects; with facets above and below, this is an active weak layer that will persist for a long time.

Avalanche Summary

With 30cm overnight and increasing SW'ly winds, expect a natural avalanche cycle from steep alpine features (Macdonald, Tupper, N Cheops). Where the new storm slabs dig down to the Nov 5 crust/facet layer, large avalanches to sz 3 can be expected.

If you observe an avalanche or have useful snowpack info, please post to the MIN on the AvCan site.

Confidence

Problems

Storm Slabs

An icon showing Storm Slabs

Where the wind has stiffened the new snow, expect reactive soft slabs in the immediate lee of ridge crests and exposed alpine/tree-line features.

  • Use caution in lee areas. Recent wind loading have created wind slabs.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

Steep planar slopes should be avoided, especially at and just above treeline.

Recent natural/human triggered avalanches, snowpack tests, and reports of whumphing indicate that this layer may still be triggered by the weight of a skier.

  • Avoid shallow snowpack areas where triggering is more likely.
  • Be aware of the potential for wide propagations which could result in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3.5

Valid until: Nov 26th, 2020 8:00AM