Avalanche Forecast

Issued: Apr 2nd, 2021 4:00PM

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

Avalanche Canada MBender, Avalanche Canada

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There is lots of new snow available for the wind to redistribute into lee terrain. As a result wind slabs will be the main concern when the wind speed picks up on Saturday.

Summary

Confidence

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

Weather Forecast

Friday Night: Cloudy with clear periods. Light west and southwest wind wind. Alpine high temperature near -12.

Saturday: Increasing cloud through the day. Moderate southwest wind. Alpine high temperature near -8.

Sunday: Flurries, accumulation 2-5 cm. Moderate to strong southwest wind. Alpine temperature near -5.

Monday: Continued flurries. Light southwest wind. Alpine high temperature near -7.

Avalanche Summary

With the highway closed through Thursday, we have no reports of avalanche activity from past several days. There were likely natural storm slab avalanches in the Whitepass area during an intense period of snowfall on Wednesday morning. 

Natural wind slabs around size 1-1.5 in lee and cross loaded terrainwere observed in Haines Pass on Wednesday and Thursday .

Snowpack Summary

A dump of new snow midweek brought 30-40 cm to White Pass and 25-30 cm to the hardest hit zones at Haines Pass. The new snow arrived with moderate southwest wind, loading pockets of wind slab into lee terrain features at all elevations. 

There are no deeper concerns in the snowpack around White Pass. The terrain around the Tutshi Lake/Paddy Peak area should be assessed on a slope by slope basis, as lingering snowpack weaknesses may still exist. The Wheaton's shallower snowpack is dominated by hard wind slabs overlying sugary facets and depth hoar. It's an untrustworthy snowpack structure that requires conservative terrain selection and diligent travel habits.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Extra caution is needed around cornices under the current conditions.

Problems

Wind Slabs

An icon showing Wind Slabs

New snow falling mid week is being redistributed by primarily southwest winds into lee terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 3rd, 2021 4:00PM