Avalanche Forecast

Archived

Jan 30th, 2025–Jan 31st, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Kitimat, Nass, Rupert, Seven Sisters, Shames, Howson.

The new snow needs time to strengthen and bond, avalanches remain possible.

Deeply buried layers are still a concern in very large alpine terrain.

Confidence

Moderate

Avalanche Summary

One very large natural avalanche was observed on Wednesday (size 3.5) on a northerly aspect at 1800 m. This likely failed on the buried weak layer from December. A reminder that this layer is still capable of producing large avalanches from time to time.

Wednesday's storm also caused a numbers natural avalanches at treeline and below treeline (size 1 and 2).

Snowpack Summary

20 to 40 cm of snow fell on Wednesday, with southwest winds depositing more in lee areas. This new snow may bond poorly to underlying layers, which could include:

Large surface hoar crystals in sheltered spots at treeline and below
Crusts on solar slopes
Old wind-affected snow

A layer of surface hoar from early January is buried 20 to 60 cm deep, though it's uncertain whether this layer will persist.

100 to 200 cm deep in the snowpack are layers of crust, facets, and possibly surface hoar that were buried in December. This deeper layer has recently caused very large avalanches (size 3.5)

Weather Summary

Thursday Night

Mostly cloudy with up to 3 cm of snow. 40 to 60 km/h southwest ridgetop wind. Treeline temperature -10 °C.

Friday

Mix of sun and cloud with 3 to 8 cm of snow. 20 to 40 km/h south ridgetop wind. Treeline temperature -10 °C.

Saturday

Mix of sun and cloud with 3 to 5 cm of snow. 20 to 30 km/h east ridgetop wind. Treeline temperature -12 °C.

Sunday

Sunny. 50 km/h northeast ridgetop wind. Treeline temperature -18 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Carefully manage your exposure to overhead hazards.
Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Investigate the bond of the recent snow before committing to your line.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.