Avalanche Forecast

Archived

Jan 19th, 2025–Jan 20th, 2025

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.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

Wind slabs may remain reactive to riders.

Recent avalanches on the buried weak layer bring uncertainty. Stick to low angle, supported terrain, free from overhead hazard.

Confidence

Moderate

Avalanche Summary

Avalanche activity appears to be tapering since the recent storm. On Saturday a naturally triggered size 3 occurred, likely from solar input, on a southwest slope at treeline. This appeared limited to the recent storm snow.

Several size 2 wind slab avalanches on east and southeast slopes in the alpine were reported on Friday.

Size 3 avalanches were observed during the storm, running on the buried weak layer 100-200 cm deep.

Snowpack Summary

Light snowfall will bury a large surface hoar layer on shaded slopes, and a crust on sun affected slopes. Previous storm accumulations of up to 80 cm were wind-affected by west/southwest winds in exposed areas. Settling storm snow can still be found in sheltered areas but tapers rapidly with elevation to 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

Sunday Night

Clear skies with increasing cloud. 20 to 30 km/h westerly ridgetop wind. Treeline temperature -8 °C. A small above-freezing layer sits around 1500 m overnight.

Monday

Cloudy. Up to 10 cm of snow possible for coastal areas, 2 cm expected for Shames. 40 to 50 km/h west ridgetop wind. Treeline temperatures start the day at -10 °C and rise to -4 °C.

Tuesday

Cloudy with no snow. 30 to 40 km/h northwest ridgetop wind. Treeline temperature -4 °C.

Wednesday

Cloudy with 10 cm of snow. 30 to 40 km/h northwest ridgetop wind. Treeline temperature -3 °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.
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.