Avalanche Forecast

Issued: Mar 24th, 2021 8:13AM

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

Andrew Jones,

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A persistent weak layer is buried approximately 50cm. This is a critical depth for larger skier-triggered avalanches. Dig down and take a look!

Summary

Weather Forecast

Scattered flurries today with 5cm of accumulation and gusty winds as a cold front sweeps across BC.  Freezing levels rise to 1600m and the alpine temperature will climb to -4.  A slight break in precipitation for tomorrow, but light snow and strong wind return to the forecast on Friday.  March is expected to go out like a lion with 25cm on Sunday.

Snowpack Summary

Strong southerly winds accompanied 10cm of new snow overnight.  The new snow adds to an existing load that sits atop the March 18th weak layer which presents as a crust on solar aspects and surface hoar on shaded aspects. March 18th is sensitive to skier triggering in areas where wind slabs have developed.  Cornices are large and fragile.

Avalanche Summary

Several size 2-2.5 and one size 3.0 wind slab avalanches were observed on north aspects in the highway corridor.  A field team was able to skier control two size 1.0 windslabs in the Cheops South #5 avalanche path, and they observed several natural dry loose avalanches up to size 2.0 in the Connaught Creek drainage.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Wind Slabs

An icon showing Wind Slabs

Strong winds have created a wind slab problem in exposed areas at treeline and above. These slabs are 15-30cm think and are reactive to human triggers. Extra caution is required where micro terrain features contribute to pockets of wind loading.

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

The March 18th persistent weak layer is buried approximately 50cm and appears as a crust on solar aspects and surface hoar on shaded aspects at treeline. This layer is most reactive in areas where wind loading has increased slab cohesion.

  • Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3

Valid until: Mar 25th, 2021 8:00AM