Avalanche Forecast

Archived

Apr 13th, 2025–Apr 14th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Northwest Coastal, Northwest Inland, Boundary, Stewart, Kispiox, Ningunsaw, Ningunsaw, Ningunsaw.

Wind slabs are expected to remain reactive to human triggers, especially in lee features.

Avoid areas where the snow is wind effected.

Confidence

Moderate

Avalanche Summary

Over the past week, explosive-controlled avalanches up to size 3 have been reported daily, involving cornice failures, wind slabs, and wet loose.

Last Friday, a failing cornice triggered a size 3 avalanche on an eastern slope in the alpine. This avalanche is believed to have occurred on the March 5th surface hoar layer.

Where a thick, supportive surface crust is found, we expect that triggering avalanches on buried weak layers is unlikely.

Snowpack Summary

5 to 25 cm of new snow sits on variably wind affected snow in open terrain at upper elevations. A crust is found up to 1800 m and higher on solar slopes.

Three layers of note currently exist in the upper-mid snowpack.

A layer of surface hoar and a crust that formed in mid-March can be found 50 to 80 cm below the snow surface.
Another layer of surface hoar that formed in early March can be found at a depth of 70 to 120 cm.
A layer of facets, surface hoar, and/or a crust from mid-February is buried 120 to 200 cm deep.

The remainder of the snowpack is well consolidated, and there are no current concerns.

Weather Summary

Sunday Night

Cloudy with 0 to 5 cm of snow. 20 to 50 km/h south ridgetop wind. Treeline temperature -1 °C. Freezing level 900 m.

Monday

Cloudy with up to 10 cm of snow. 30 to 50 km/h south ridgetop wind. Treeline temperature -1 °C. Freezing level 1100 m.

Tuesday

Partly cloudy. 40 to 70 km/h southwest ridgetop wind. Treeline temperature -3°C. Freezing level 1000 m.

Wednesday

Mix of sun and cloud. 10 to 30 km/h southwest ridgetop wind. Treeline temperature -3°C. Freezing level 1000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
Cornice failures could trigger large and destructive avalanches.
Avalanche activity is unlikely when a thick melt-freeze crust is present on the snow surface.

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.