North Columbia

Buried weak layers will likely cause dangerous avalanche conditions to persist.

Avoid travelling under large slopes.

The avalanche cycle continued on Wednesday, with many large storm and persistent slab avalanches failing deep within the snowpack, either below the storm snow or on the crust from November. The larger avalanches (size 3-3.5) were running from the alpine and well below treeline.

50 to 100 cm of snow has fallen this week over a weak surface hoar layer and/or weak faceted snow. Surface hoar is most likely in tree openings sheltered from the wind, whereas faceted snow may be found in wind-exposed terrain into the alpine. Facets may be associated with a hard melt-freeze crust that formed in the middle of November. This layer has recently produced large avalanches.

Thursday Night
Mostly cloudy with 2 to 5 cm of snow. 20 km/h west ridgetop wind. Treeline temperature -7 °C.

Friday
Cloudy with 10 to 15 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -6 °C.

Saturday
Mostly cloudy with 5 to 15 cm of snow. 20 to 50 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level rising to 2500 m.

Sunday
Cloudy with 15 to 25 mm of precipitation as snow or rain at treeline. 40 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1900 m.

More details can be found in the Mountain Weather Forecast.

• Use conservative route selection. Choose simple, low angle terrain with no overhead hazard.
• Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
• Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.