Avalanche Forecast

Archived

Jan 18th, 2025–Jan 19th, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kitimat, Nass, Rupert, Seven Sisters, Shames, Howson, Microwave-Sinclair.

Seek out sheltered, low-angle terrain while the recent storm snow settles.

Human-triggered avalanches are likely, with deep instabilities that have produced large avalanches recently.

Confidence

Moderate

Avalanche Summary

Friday, avalanches up to 200 m wide on steep, shady slopes were reported in the Shames backcountry. Get more details here. Several size 2 wind slab avalanches on east and southeast slopes in the alpine were also reported throughout the region.

Thursday, a natural avalanche cycle up to size 3 occurred.

Natural avalanche activity will taper but human-triggered avalanches are likely through the weekend.

Snowpack Summary

Earlier this week, the storm dropped 30 to 80 cm of snow across the region. At upper elevations, the surface is wind-affected. Reports suggest soft surface snow, with sluffing, on sheltered slopes and at lower elevations.

Expect to find deeper deposits of reactive wind slab on east and northeast slopes. Changing winds may start to load south-facing slopes throughout the weekend. The recent storm snow tapers dramatically with elevation, where 5 to 10 cm sits above a firm melt-freeze crust.

50 to 100 cm deep a layer of surface hoar, facets, or a thin crust exists.

A persistent weak layer of surface hoar and facets overlying a crust is buried 120 to 200 cm deep.

Weather Summary

Saturday Night

Clear. 30 to 40 km/h north ridgetop wind. Treeline temperature -12 °C.

Sunday

Mostly clear. 10 to 20 km/h northeast ridgetop wind. Treeline temperature -8 °C. An above-freezing layer in the alpine.

Monday

Few clouds. 20 to 40 km/h west ridgetop wind. Treeline temperature -5.

Tuesday

Cloudy with trace snow. 30 to 40 km/h northwest ridgetop wind. Treeline temperature -5 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Choose low-angled, sheltered terrain where new snow hasn't been wind-affected.
Recent wind has varied in direction, so watch for wind slabs on all aspects.
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.