Avalanche Forecast

Archived

Mar 23rd, 2025–Mar 24th, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Regions

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

Be cautious as you transition into wind effected terrain.

It is still possible for small avalanches to step down to weak layers deep in the snowpack and produce large destructive avalanches.

Confidence

Moderate

Avalanche Summary

On Saturday, there were reports of numerous persistent slab and storm slab avalanches up to size 2.5, primarily occurring on northern aspects.

There were also reports of human-triggered persistent slab avalanches at treeline up to size 2.

Snowpack Summary

50-80 cm of recent snow has accumulated over previously wind-affected surfaces and crusts on steep south-facing terrain.

Three layers of concern currently exist in the upper-mid snowpack. Surface hoar that formed in mid-March can be found 65 to 100 cm below the snow surface. Below this, another layer of surface hoar that formed in early March can be found at a depth of 100 to 150 cm. Additionally, a layer of facets, surface hoar, and/or a crust from mid-February is buried 100 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 1 cm of snow. 20 to 50 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 900 m.

Monday

Mostly cloudy. 20 to 40 km/h south ridgetop wind. Treeline temperature -2 °C. Freezing level 1200 m.

Tuesday

Cloudy. 30 to 40 km/h southwest ridgetop wind. Treeline temperature 0 °C as freezing levels rise to 1500 m.

Wednesday

Cloudy. 5-10 cm of snow. 20 to 30 km/h southwest ridgetop wind. Treeline temperature 0 °C, freezing levels rise to 1600 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for large avalanches due to buried weak layers.
Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Minimize exposure during periods of heavy loading from new snow and wind.

Problems

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.

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.