Avalanche Forecast

Issued: Mar 17th, 2024 4:00PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is high. Known problems include Persistent Slabs, Loose Wet and Cornices.

Avalanche Canada DH, Avalanche Canada

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Avoid avalanche terrain!

Strong sunshine and above freezing alpine temperatures are causing a widespread natural avalanche cycle

Widespread large natural avalanches are expected

Summary

Confidence

High

Avalanche Summary

Since the warm up began on Friday we have seen numerous loose and wet slab avalanches from solar aspects, some very large and failing on the Feb 3rd layer. Notably a size 4 from the west face of Cheops and size 3 beside the Grizzly couloir

Expect natural avalanches to increase in size and frequency with continued warming.

Natural avalanches on the persistent weak layer (over 1m deep) are expected to become widespread as the warmth penetrates deeper into the snowpack.

Snowpack Summary

Expect a very thin crust to form overnight that will break down quickly by mid morning from above zero temps and intense sun. When that happens the upper snowpack will turn to mush.

A previous suncrust, down 20-40cm, may make a sliding layer for wet slabs.

80-140cm of settled snow sits above a sugary facet layer. These facets are poorly bonded to the widespread, firm crust from Feb 3rd. This is a significant persistent weak layer and will be a concern for the foreseeable future.

Weather Summary

The warm weather will continue for two more days keeping the avalanche danger high. By mid week the freezing level (FZL) will begin to lower and temps return to more seasonal values and snow on Wednesday.

Tonight: Alpine low 2°C, light W winds, FZL 1100m with a temperature inversion.

Mon: Warm and sunny, low 1°C, high 3°, FZL 2700m, light W winds.

Tues: Mix of sun and cloud, low 1°C, high 4°C, FZL 2100m, light W winds.

Terrain and Travel Advice

  • Avoid exposure to overhead avalanche terrain as temperatures increase.
  • If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid exposure to slopes that have cornices overhead.
  • Avoid traveling in runout zones. Avalanches have the potential to run to the valley floor.

Problems

Persistent Slabs

An icon showing Persistent Slabs

This crust-facet combo (Feb 3rd) was created by a rain event followed by an extended cold, clear period without snow earlier this month. 80-140cm now sits on this persistent weak layer. Natural avalanche activity is expected on this layer as warm temperatures continue to penetrate the snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Loose Wet

An icon showing Loose Wet

With above freezing temps into the alpine, loose snow avalanches are expected to run on all aspects as the snowpack warms.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2.5

Cornices

An icon showing Cornices

Cornices are being weakened by strong sun and hot alpine temperatures. A falling cornice itself is a major hazard but may also trigger large destructive slab avalanches on the slopes below.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1.5 - 2.5

Valid until: Mar 18th, 2024 4:00PM

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