Avalanche Forecast

Issued: Mar 22nd, 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 mconlan, Avalanche Canada

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The wind is forecast to pick up on Tuesday, which could form new wind slabs. Assess for slab formation in your riding area and seek sheltered terrain for the softest conditions.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

MONDAY NIGHT: Cloudy with isolated flurries, accumulation 1 to 3 cm, 20 to 30 km/h southwest wind, alpine temperature -11 C.

TUESDAY: Cloudy with snowfall, accumulation 2 to 5 cm, 40 km/h southwest wind, alpine temperature -10 C.

WEDNESDAY: Mostly cloudy, 20 km/h west wind, alpine temperature -10 C.

THURSDAY: Cloudy with snowfall, accumulation 2 to 5 cm, 50 km/h southwest wind, alpine temperature -8 C.

Avalanche Summary

There have been no recent avalanche observations, with the weekend's reports suggesting that the recent snow is bonding to previous surfaces and previously formed wind slabs are unreactive. Looking ahead, new wind slabs may develop on Tuesday and they could be triggered by riders on steep wind-loaded slopes.

Snowpack Summary

Around 20 cm of recent snow overlies previous surfaces, including a hard melt-freeze crust on south aspects, widespread wind effect in the alpine and in wind-exposed terrain around treeline, and settled dry snow in sheltered terrain at treeline elevations. The recent snow may be blown into new wind slabs on Tuesday with forecast strong southwest wind.

There are no deeper concerns around White Pass.

Substantial spatial variability exists within the snowpack around the Tutshi Lake/Paddy Peak area. Terrain should be assessed on a slope by slope basis, as lingering weaknesses may still exist.

The Wheaton's continental snowpack is dominated by hard wind slabs overlying sugary facets and depth hoar. It's an untrustworthy snowpack structure that requires good terrain selection and travel habits.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid lee and cross-loaded terrain.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Avoid exposure to slopes that have cornices overhead.

Problems

Wind Slabs

An icon showing Wind Slabs

Strong southwest wind may form new wind slabs on Tuesday, blowing around the 20 cm of recent soft snow. The most likely place to trigger them would be in steep leeward or cross-loaded terrain. These shallower slabs will sit on hard wind slabs in exposed terrain, which are old and unlikely to be triggered.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 24th, 2021 4:00PM