Avalanche Forecast

Issued: Mar 24th, 2020 4:00PM

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

Avalanche Canada cgarritty, Avalanche Canada

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Forecast confidence is low due to a lack of field observations. New and reactive wind slabs are expected to exist in higher elevation terrain.

Summary

Confidence

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

Weather Forecast

Tuesday night: Clear. Moderate north winds, increasing into the morning.

Wednesday: Sunny. Moderate to strong north winds shifting west. Alpine high temperatures around -7.

Thursday: Cloudy with scattered flurries bringing up to 5 cm of new snow, easing overnight. Moderate to strong southwest winds. Alpine high temperatures around -8.

Friday: Cloudy with isolated flurries and a trace of new snow, increasing overnight. Moderate to strong southwest winds. Alpine high temperatures around -9.

Avalanche Summary

No new avalanches were observed on Monday or Tuesday from limited reports. 

Looking forward, recently formed wind slabs may remain reactive to human triggering over the coming days.

Snowpack Summary

Around 5 to 15 cm of snow fell Sunday night with northeast wind. Wind slabs may form in areas where the wind speed picks up on Tuesday night. Any new slabs will sit on a melt-freeze crust on sun-exposed slopes and over previously wind-affected snow on other aspects. Slabs formed over crust may take a bit longer to stabilize.

A weak layer of surface hoar crystals buried early March may be found around 30 to 50 cm deep, particularly in sheltered terrain around treeline. Recent observations of this layer are limited.

An early-season layer of faceted grains and melt-freeze crust near the base of the snowpack may linger. The most suspect locations to trigger this layer would be where the snowpack is thin near rocky outcroppings. A large load, such as a cornice fall, also has the potential of triggering it.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
  • Make conservative terrain choices and avoid overhead hazard.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs may form as forecast north winds pick up over Tuesday night, transporting recent snowfall. Use added caution at higher elevations, particularly near ridge lines.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

A weak layer of surface hoar crystals is buried around 30 to 50 cm in sheltered, shady terrain around treeline. Recent warm conditions have likely promoted bonding of this layer but there is uncertainty about whether it is still a problem.

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

Elevations: Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Mar 25th, 2020 5:00PM

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