Avalanche Forecast

Issued: Apr 1st, 2022 4:00PM

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

Avalanche Canada swerner, Avalanche Canada

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Fresh wind slabs may be reactive to human triggering at upper elevations, especially where they sit above a crust. 

Summary

Confidence

Moderate - Forecast precipitation (either snow or rain) amounts are uncertain.

Weather Forecast

Unsettled weather is forecast for the weekend. This will bring mostly cloudy skies, new snow of 5-10 cm, and moderate to strong southwest winds at ridgetop. Freezing levels will rise to 1500 m during the day and drop overnight. 

Avalanche Summary

On Thursday, several wind slabs and dry loose avalanches were reported up to size 2. They looked to be approximately 24 hours old. 

 On Wednesday, no significant avalanche activity was reported. Sloughing from steep terrain was seen and older wind slabs up to size 2. 

On Tuesday, in the north of the region small (size 1) wind slabs were reactive to human-triggering in the alpine. In the south of the region, a natural storm/wind slab cycle up to size 3 occurred, triggered by warm temperatures and strong solar radiation. The most reactivity was noted on south-facing aspects.

A widespread wet loose natural avalanche cycle up to size 3 occurred on Monday on all aspects and elevations. The most activity occurred below treeline. 

Snowpack Summary

Above 2000 m, 10-20 cm of new snow overlies up to 30 cm of denser snow that tapers rapidly with elevation. A melt-freeze crust exists on the surface up to 2000 m and higher on solar aspects. Below the crust, the top 10-30 cm of the snowpack is moist. This brings 50-60 cm over the mid-March interface at upper elevations. Westerly winds have formed reactive wind slabs on leeward terrain in the alpine and exposed treeline terrain.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Problems

Wind Slabs

An icon showing Wind Slabs

New snow and strong southwest winds may build fresh and reactive wind slabs. Wind slabs can be expected in leeward terrain features in the alpine and treeline. These wind slabs will be most reactive where they overlie a slick crust.  

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 2nd, 2022 4:00PM