Avalanche Canada ahanna, Avalanche Canada

Northwest Coastal Avalanche Forecast

Jan 14th, 2020 4:00PM

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

It is dangerously cold and windy out there right now. Save your toes for the warmer temperatures and new snowfall this weekend.

Summary

Confidence

Moderate -

Weather Forecast

Tuesday night: Clear. Strong valley outflows with moderate alpine wind from the northeast. Alpine temperatures around -27 C.

Wednesday: Sunny. Strong approaching extreme valley outflows with moderate alpine wind from the east. Alpine temperatures around -26.

Thursday: Mix of sun and cloud. Moderate southeast winds. Alpine temperatures around -20.

Friday: Mix of sun and cloud. Moderate south to southeast winds. Alpine temperatures around -20.

Avalanche Summary

A natural windslab cycle, size 2-3 was observed Sunday and Monday morning amid reverse loading by strong outflow winds. In an isolated incident, a crown depth of 2 m was observed on a southeast aspect in the alpine. It is suspected to have stepped down to deep persistent layers from mid December. Cornice and serac failures were also observed, as they typically become brittle in the cold.

Looking forward, windslabs will likely become less reactive as they lose cohesion in the cold temperatures. In sheltered areas, unconsolidated snow may be reactive to human triggering as dry loose sluffs.

Snowpack Summary

Extensive wind effect observed at all elevations. North to east aspects in the alpine have been wind scoured, with isolated hard windslab in lees, and notable cornice growth. Not much snow remains for wind transport by the forecast continued outflow. Snow in protected areas is unconsolidated and well preserved by the cold temperatures.

The mid to lower snowpack is generally well consolidated. Layers of note include a crust 1 m deep, found below 1400 m and a couple of layers of surface hoar 1.5 m deep. The previous storm cycle was a good test of these layers, with only an isolated case of suspected step down to one of the surface hoar layers.

Terrain and Travel

  • Keep your guard up at lower elevations. Wind slab formation has been extensive.
  • Be alert to conditions that change with elevation, aspect and exposure to wind.
  • Avoid terrain traps where the consequence of any avalanche could be serious.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Strong outflow winds have blown snow into wind slabs extensively in the alpine and in open areas at treeline and below. They will likely become less reactive as they lose cohesion in the cold temperatures.

Aspects:

South East, South, South West, West, North West.

Elevations:

All elevations.

Valid until: Jan 15th, 2020 5:00PM