Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Mar 30th, 2023–Mar 31st, 2023

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.

Regions

Northwest Coastal, Kitimat, Nass, Rupert, Seven Sisters, Shames, Stewart, Howson.

Watch for cornices and isolated wind slabs if travelling into alpine terrain.

Confidence

Moderate

Avalanche Summary

Most avalanche activity this week has been limited to small (size 1) wet loose avalanches. Some natural cornice failures have been observed, but have not triggering slabs on slopes below.

However, a few outliers - large slab avalanches - have been reported throughout the region. Although we don't think we have a widespread problem, it's something to keep in mind as the spring warms up. On Monday, a size 2.5 wet slab was reported south of Terrace, originating from a steep and rocky start zone on a northwest aspect near treeline. On Tuesday, two large avalanches ranging from size 2.5-3 were observed in the alpine north of Stewart, possibly triggered by cornices and running on a weak layer buried in January that had previously not shown any signs of reactivity for several weeks.

Snowpack Summary

Up to 10 cm of new snow will fall on Friday with deeper deposits in lee terrain. In most areas this snow is falling on moist or crusty snow layers, except shaded terrain above roughly 1400 m where the snow has remained dry over the past week. The lower snowpack is strong and bonded.

Weather Summary

Thursday night

Increasing cloud, light flurries with 1 to 5 cm of snow, 40 km/h southwest wind, treeline temperatures around -5 °C with freezing level dropping to 500 m.

Friday

Cloudy, scattered flurries with 2 to 5 cm of snow (and some localized accumulations of 10 cm along the immediate coast), 50 km/h south wind, treeline temperatures around -3 °C with freezing level climbing to 800 m.

Saturday

Around 5 cm overnight then clearing to a mix of sun and cloud, 30 km/h southwest wind, treeline temperatures around -4 °C with freezing level climbing to 800 m.

Sunday

Sunny, no precipitation, 10 km/h northeast wind, treeline temperatures around -1 °C with freezing level climbing to 1100 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Carefully evaluate steep lines for wind slabs.
  • Avoid exposure to slopes that have cornices overhead.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Problems

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.

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.