Avalanche Forecast

Archived

Jan 7th, 2025–Jan 8th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Northwest Coastal, Boundary, Kitimat, Nass, Rupert, Seven Sisters, Shames, Stewart, Howson, Ningunsaw, Ningunsaw, Ningunsaw.

It's a good day to make conservative choices.

Stick to low-angle below treeline slopes, with no overhead hazard from big avalanche terrain.

Confidence

Moderate

Avalanche Summary

On Monday, north of Stewart, a vehicle triggered a size 1.5 slab on the persistent weak layer. It failed on a northwest slope in the alpine. A few wind slabs size 1 to 2 were also observed across the region.

We expect a widespread natural avalanche cycle to be ongoing, and to continue overnight and into Wednesday. The potential for human-triggered avalanches is expected to be almost certain during this stormy period.

Snowpack Summary

15 to 30 cm of snow fell throughout the day Tuesday. An additional 10 to 20 cm accompanied by moderate to strong westerly ridgetop winds is forecast to fall overnight. This combination is expected to form fresh storm slabs and deep wind-deposits on leeward slopes.

We expect the accumulated storm slabs to be especially touchy wherethey are sitting on a layer of buried surface hoar, facets, or a thin crust, in some areas.

A persistent weak layer of surface hoar and facets overlying a crust. It is buried 60 to 120 cm deep in the southern parts of the region, and up to 200 cm deep in areas north of Stewart.

The snow surface may be moist, wet or crusty below 1100m.

Weather Summary

Tuesday Night

Cloudy with 10 to 20 cm of snow near Terrace, 0 to 5 cm near Stewart. 40 km/h west ridgetop wind. Treeline temperature -2 °C. Freezing level ~ 1100m.

Wednesday

Cloudy, with 0 to 3 cm of snow. 35 to 45 km/h west ridgetop wind. Treeline temperature -2°C. Freezing level ~ 1100m.

Thursday

Cloudy with 15 to 25 cm of snow. 80 to 100 km/h south ridgetop wind. Treeline temperature -1 °C. Freezing level rising to ~1400 m near Terrace.

Friday

Cloudy with 2 to 10 cm of snow. 50 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level rising to ~1000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Avoid exposure to overhead avalanche terrain; avalanches may run surprisingly far.
Don't let the desire for deep powder pull you into high consequence terrain.

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.