Avalanche Forecast

Issued: Mar 29th, 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 kdevine, Avalanche Canada

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Fresh snow is expected in the region on Tuesday and Wednesday with strong southerly winds. Expect to find fresh and potentially reactive wind slabs, with the peak of this activity likely occurring on Wednesday. Back off if you encounter whumpfing, cracking, or hollow sounds.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Monday Night - Mainly cloudy with isolated flurries / moderate to strong southwest wind / alpine low temperature near -12 

Tuesday - Mainly cloudy with flurries, 5-10 cm / strong southwest wind / alpine high temperature near -10 

Wednesday - Snow, 10-15 cm / strong south wind / alpine high temperature near -10 

Thursday - A mix of sun and cloud / light southwest wind / alpine high temperature near -12 

Avalanche Summary

Winds are expected to shift back to the south and west over the coming days, which could result in further wind loading and the formation of fresh and reactive wind slabs, especially with fresh snow expected on Tuesday and Wednesday.

A significant wind event, with extreme north winds in the White Pass area on Saturday night, triggered a widespread natural avalanche cycle. 

Snowpack Summary

Recent strong winds from a variety of directions have likely formed wind slabs on many aspects. 5-10 cm of new snow is expected on Tuesday with another 10-15 cm on Wednesday. This likely means that fresh wind slabs will continue to form and may be reactive to human triggering. 

There are no deeper concerns in the snowpack around White Pass.

Substantial spatial variability likely still exists in the snowpack around the Tutshi Lake/Paddy Peak area. The terrain here 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.
  • Be aware of highly variable recent wind loading patterns.
  • Avoid exposure to slopes that have cornices overhead.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs may be found on a variety of aspects due to recent variable wind direction. Fresh wind slabs are expected to form on Tuesday and Wednesday with new snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 31st, 2021 4:00PM

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