Avalanche Forecast

Issued: Dec 16th, 2024 4:00PM

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

Avalanche Canada Avalanche Canada, Avalanche Canada

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A storm is set to hit the Island late Tuesday afternoon.Minimize your exposure to avalanche terrain during periods of heavy loading from new snow / rain and wind.

Summary

Confidence

Low

Avalanche Summary

On Sunday, shooting cracks and small slabs were triggered by riders near Mt.Arrowsmith.

On Saturday, several storm slab avalanches sized 1 to 1.5, were rider-triggered near Mt.Washington.

On Friday, our field team reported shooting cracks from their skis on Mt.Cokely.

We expect the old storm slabs to become increasingly difficult to trigger, while new, reactive slabs are expected to form with the approaching storm on Tuesday afternoon.

Snowpack Summary

25 to 60 cm fell over the last storm. An additional 10 to 25 cm is expected to fall Tuesday afternoon, with very heavy rain starting after 3pm. This storm is forecast to favour the south and western parts of the Island with higher precipitation.

Strong to extreme southeasterly winds are expected to scour windward slopes in many areas, creating deep deposits far downslope in lees. A thick hard crust tops the surface below around 1200 m.

The mid snowpack and lower snowpack is well-settled with no layers of concern.

Total snow depths at treeline vary; from 240 cm near Mt. Washington, to 140 cm near Mt Cain.

Weather Summary

Monday Night

Cloudy, 0 to 2 cm of snow. 30 to 40 km/h southeast ridgetop wind. Treeline temperature -2 °C.

Tuesday

Cloudy, with 10 to 25 cm of snow / moderate to heavy rain in the afternoon. 60 to 80 km/h southeast ridgetop wind. Treeline temperature 1 °C. Freezing level rising from 1000 to 2700 m in the late afternoon.

Wednesday

Mostly cloudy. 35 to 50 km/h south ridgetop wind. Treeline temperature 4 °C. Freezing level 1200 m.

Thursday

Cloudy with with periods of light rain. 80 to 90 km/h south ridgetop wind. Treeline temperature 4 °C. Freezing level rising to 2700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Storm slab size and sensitivity to triggering will likely increase through the day.
  • Be especially cautious as you transition into wind-affected terrain.

Problems

Storm Slabs

An icon showing Storm Slabs

If you see fresh storm slabs building with heavy snowfall and wind, minimize your exposure and choose more conservative terrain. The most reactive slabs will be on lee northerly slopes near ridgetops.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 17th, 2024 4:00PM

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