Avalanche Forecast

Issued: Dec 3rd, 2021 4:00PM

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

Garth Lemke,

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The Maligne and Icefields Parkway just opened. Expect the skiing to be sensational but keep your radar on high alert with the new snow input and changing conditions. Keep you exposure low as the new snow needs time to adjust. 

Summary

Weather Forecast

Saturday will be cloudy, sunny periods, isolated flurries, -9 C, light ridge wind. Sunday will be similar but colder at -19 °C to -16 °C. Monday will be much the same.

Snowpack Summary

About 40 cm of snow fell from Nov 30 to Dec 1. Light to moderate SW winds are blowing it into wind slabs or stripping windward features to ground. The storm snow came in warm but it surprisingly remains dry and light except at low elevations where it rained. The midpack is supportive over a crust - Facet - depth hoar combo near the ground. 

Avalanche Summary

Friday's patrol noted a reduction in natural activity yet a couple of recent size 3's deep slabs running full path were recorded. Thursday's explosive control work observed an avalanche cycle up to size 3 being wind and deep persistent slabs on the ground or the basal crust. Two size 3s were observed at Maligne north of Joffre Creek on Thursday.

Confidence

Due to the number and quality of field observations

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

We are observing deep slab releases running far yet natural activity is decreasing as the recent new snow stabilizes. Triggering it would be a high consequence event so cautious decisions and a thorough investigation is necessary.

  • Avoid thin rocky or unsupported terrain features.
  • Use caution on open slopes and convex rolls

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Wind Slabs

An icon showing Wind Slabs

Expect to encounter wind slabs where wind has influence such as Alpine and exposed treeline locations from, but not limtied to. NW to SE aspects. Natural activity has tapered but only recently.

  • Use caution in lee areas. Recent wind loading have created wind slabs.
  • Use conservative route selection, choose moderate angled and supported terrain with low consequence.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Dec 4th, 2021 4:00PM