Avalanche Forecast

Issued: Mar 23rd, 2021 4:00PM

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

Avalanche Canada ahanna, Avalanche Canada

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Strong wind forecast overnight will likely transport recent snow into fresh, reactive wind slabs at upper elevations. Watch for signs of instability like shooting cracks in wind loaded lee features such as beneath ridge crests and roll-overs.

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

Tuesday night: Increasing cloud. Moderate westerly wind, strong above 2000 m. Alpine high temperatures around -5. Freezing level 1200 m.

Wednesday: Up to 5 cm new snow. Moderate westerly wind. Alpine high temperatures around -5. Freezing level 1500 m.

Thursday: Mix of sun and cloud. Light wind. Alpine high temperatures around -4. Freezing level 1700 m.

Friday: Mix of sun and cloud. Moderate westerly wind. Alpine high temperatures around -1. Freezing level 2000 m.

Avalanche Summary

Storm slabs were reactive to explosives on Monday, size 1-1.5. With strong overnight winds forecast, more slab activity is anticipated for Tuesday.

A large (size 2) glide slab occurred overnight Friday on a lower elevation slope on Mt. Fernie. It may have been coaxed into action by overnight rainfall. This serves as a great reminder to avoid slopes with glide cracks on them at all times. They are inherently unstable and can release at any time.

Snowpack Summary

20-30 cm of new snow has been accumulating incrementally over recent days on top of wind affected surfaces at higher elevations and over a mix of refrozen or still wet snow at treeline and below. This new snow is most likely being blown around by strong winds forecast overnight Tuesday and into Monday morning, forming fresh wind slabs in lee terrain features at upper elevations. The snowpack is otherwise well settled and strong.

Terrain and Travel

  • Be alert to conditions that change with elevation.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.

Problems

Wind Slabs

An icon showing Wind Slabs

Strong westerly wind forecast overnight will likely transport recent snow into fresh, reactive wind slabs at upper elevations. Watch for wind loaded pockets in lee terrain features such as beneath ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 1.5

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