Avalanche Forecast

Archived

Apr 3rd, 2025–Apr 4th, 2025

Alpine

Natural avalanches possible, human triggered probable.

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.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

Another warm-up brings rising avalanche risk. Read the new forecasters' blog.

Uncertainty is due to how buried persistent weak layers will react to the upcoming warm weather.

Confidence

Moderate

Avalanche Summary

On Monday, a few wet loose avalanches were seen from steep terrain features. Where a thick, supportive surface crust is found, we expect that triggering avalanches on buried weak layers is unlikely.

Evidence from last week's natural avalanche cycle continued to be reported with very large slab avalanches (to size 4) failing on buried persistent weak layers.

Snowpack Summary

A melt-freeze crust has formed on most surfaces. Dry snow persists on northerly aspects at upper elevations.

Three persistent weak layers remain notable in the snowpack and have been responsible for recent large avalanches. Surface hoar that formed in mid-March can be found 50 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.

Weather Summary

Thursday Night

Mainly clear. 10 to 20 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1400 m.

Friday

Mix of sun and cloud. 30 to 40 km/h southwest ridgetop wind. Treeline temperature +6 °C. Freezing level 2000 m.

Saturday

Mix of sun and cloud. 40 to 60 km/h south ridgetop wind. Treeline temperature +4 °C. Freezing level 2000 m.

Sunday

Mostly cloudy with 5 to 10 cm of new snow. 30 to 40 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1400 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avalanche activity is unlikely when a thick melt-freeze crust is present on the snow surface.
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.
Back off slopes as the surface becomes moist or wet with rising temperatures.

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.