Avalanche Forecast

Issued: Nov 29th, 2021 4:00PM

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

Avalanche Canada ahanna, Avalanche Canada

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Uncertainty around conditions is best managed through a conservative approach. Avoid recently wind loaded areas in the alpine and upper treeline.

Summary

Confidence

Low - Uncertainty is due to limitations in the field data.

Weather Forecast

Monday night: Increasing cloud. Southwest wind becoming strong. Freezing level 1900 m.

Tuesday: Flurries, up to 5 cm. Strong southwest wind. Freezing level 2000 m.

Wednesday: 10-20 cm new snow, rain below 2000 m. Strong southwest wind. Freezing level 2400 m.

Thursday: 5-10 cm overnight then clearing. Moderate westerly wind. Freezing level dropping 2000 to 1700 m.

Avalanche Summary

Neighboring Kananaskis Country reported a widespread natural avalanche cycle up to size 3 running full path on Sunday as well as a few naturals up to size 2 on Monday. Several of these large avalanches stepped down to a buried crust.

Reports in the region remain limited. If you go out in the mountains, please share your observations and/or photos on the Mountain Information Network! 

Snowpack Summary

With large gaps in field data, uncertainty exists around current conditions. We suspect wind pressed surfaces in the alpine and moist to wet snow treeline and below.

Two crusts are found in the snowpack: the mid-November rain crust buried 20-30 cm and reported up to 2100 m, and a crust from early November found at the bottom of the snowpack up to 2300 m, this crust is being to break down and facet. The heavy storm this week test the potential for failure on this layer.

Snowpack depths range from 40-150 cm at treeline elevations. Higher elevations may hold a deeper snowpack, but also be more heavily impacted from recent winds. Snowpack depths decrease rapidly below 1900 m.

Early season hazards are very real right now, be wary of thin/shallow snowpacks, rocks, stumps, creeks, and other sharks hidden under fresh snow.

Terrain and Travel

  • In times of uncertainty conservative terrain choices are our best defense.
  • Stay off recently wind loaded slopes until they have had a chance to stabilize.
  • Be alert to conditions that change with elevation and wind exposure.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs may be reactive, especially to human triggers. There may be potential for wind slab avalanches to step down to a buried crust, producing very large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Nov 30th, 2021 4:00PM

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