Avalanche Canada cgarritty, Avalanche Canada

Northwest Coastal Avalanche Forecast

Jan 11th, 2020 4:00PM

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

Cooling temperatures and strong winds are the story for Sunday. Expect danger to increase over the day as snow is redistributed into reactive new wind slabs. This is expected to occur in exposed areas at all elevations.

Summary

Confidence

High -

Weather Forecast

Saturday night: Clearing. Light northwest winds shifting northeast and increasing.

Sunday: Sunny. Moderate to strong northeast winds, increasing over the day. Alpine high temperatures around -22.

Monday: Sunny. Light to moderate northeast winds. Alpine temperatures around -25.

Tuesday: Sunny. Light to moderate northeast winds. Alpine temperatures around -24.

Avalanche Summary

Active avalanche conditions existed throughout the region on Friday, however visibility limited observations. Rapid loading from snowfall and wind resulted in natural avalanche activity focused toward higher elevations exposed to strong winds.

Looking forward, wind redistributed snow from Friday's storm will remain our primary concern. Under forecast cool temperatures, sheltered snow may continue to react to human triggers as dry loose sluffs. Greater danger should be expected in exposed areas where winds have created deeper and more reactive slabs. 

Snowpack Summary

40-60 cm of new snow accumulated over the region on Friday. The new snow mainly buried wind-affected surfaces at alpine and upper treeline elevations. It may cover a new layer of surface hoar at lower elevations and in sheltered areas or a thin sun crust on steeper south-facing slopes.

Below the new snow interface, 80-100 cm of older storm snow, also wind affected, has been forming a strengthening bond with an underlying crust up to treeline and yet another array of wind affected surfaces at higher elevations.

Below these layers the snowpack is generally well consolidated. Two older layers of surface hoar are now buried 130-180 cm deep. The recent storm cycle was a good test of these layers, with no reports of avalanches stepping down to them.

Terrain and Travel

  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Avoid freshly wind loaded terrain features.
  • Seek out sheltered terrain where new snow hasn't been wind-affected.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Very Likely

Expected Size

1 - 2.5

Recent strong and variable winds have been redistributing storm snow into touchier wind slabs at all elevations and on most aspects. Fresher, touchier slabs are expected to form on south through west aspects as a result of forecast northeasterly outflow winds.

Aspects:

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

Elevations:

All elevations.

Valid until: Jan 12th, 2020 5:00PM