Avalanche Forecast

Issued: Apr 5th, 2021 2:00PM

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 shorton, Avalanche Canada

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Steady flurries and wind will make wind slab avalanches possible on steep open slopes this week.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

MONDAY NIGHT: Flurries with about 5 cm of new snow at White Pass, 30-40 km/h southwest wind, treeline temperatures drop to -8 C.

TUESDAY: Cloudy with scattered flurries and another 5 cm of snow, light north wind with some moderate gusts, treeline temperatures around -5 C.

WEDNESDAY: Mostly cloudy with some isolated flurries, light north wind, treeline temperatures around -8 C.

THURSDAY: Cloudy with flurries intensifying throughout the day with 10-15 cm of snow by the evening, 50-70 km/h south wind, treeline temperatures around -5 C.

Avalanche Summary

Over the weekend there were a few reports of natural wind slab avalanches (see a photo in this MIN report) and some size 1 wet loose avalanches on steep sun-exposed slopes. Looking forward fresh wind slabs will be the main concern.

Snowpack Summary

Light accumulations of snow over the past few days with strong southwest wind has likely left pockets of wind slabs in lee terrain features. The White Pass area has a deep snowpack without any layers of concern. The Tutshi Lake / Paddy Peak area should be assessed on a slope by slope basis, as some lingering snowpack weaknesses may still exist on isolated slopes. 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

  • Seek out sheltered terrain where new snow hasn't been wind-affected.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Fresh wind slabs will likely form on north and east facing slopes on Tuesday. Winds may shift on Wednesday and form isolated slabs on other aspects too.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 7th, 2021 2:00PM

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