Northwest Coastal

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

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.

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.

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.

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.

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.

• 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.