Avalanche Forecast

Archived

Apr 12th, 2025–Apr 13th, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

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.

Regions

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

Increasing wind and forecast heavy snowfall amounts have raised the avalanche danger.

Before venturing into challenging and complex terrain, give the new snow time to settle and bond.

Confidence

Moderate

Avalanche Summary

On Friday north of the sleeping beauty provincial park. Ski cutting produced a few small (size 1) wind slab avalanches with one large (size 2) remotely triggered persistent slab avalanche reported.

If you do head out in the mountains, please share your observations on the Mountain Information Network.

Snowpack Summary

Up to 35 cm of new snow is present on the surface above 1500 m and has buried a melt freeze crust. Past strong southerly winds has likely transported available snow, promoting wind slab development.

Dry snow exists on northerly aspects at upper elevations.

Below 1100 m the snowpack is wet and unconsolidated.

Three persistent weak layers remain notable in the snowpack.

Surface hoar that formed in mid-March can be found 50 to 100 cm below the snow surface.
A layer of surface hoar that formed in early March can be found at a depth of 100 to 150 cm.
A layer of facets, surface hoar, and/or a crust from mid-February is buried 100 to 200 cm deep.

At elevations below treeline, the snow pack is rain saturated and isothermal.

Weather Summary

Saturday Night

Mostly cloudy with 5 to 10 cm of snow. 30 to 60 km/h southwest ridgetop wind. Treeline temperature -1°C. Freezing level 1000 m.

Sunday

Cloudy with up to 15 cm snow. 50 to 70 km/h southwest ridgetop wind. Treeline temperature 0°C. Freezing level 1600 m.

Monday

Cloudy with up to 15 cm snow. 50 to 70 km/h southwest ridgetop wind. Treeline temperature 0°C. Freezing level 1600 m.

Tuesday

Cloudy with flurries. 30 to 40 km/h southwest ridgetop wind. Treeline temperature -3°C. Freezing level 700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be careful as you transition into wind-affected terrain.
Be aware of the potential for large avalanches due to buried weak layers.
Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

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.