Avalanche Forecast

On Tuesday, large persistent slab and wind slab avalanches (up to size 2.5) occurred naturally on east slopes at treeline and alpine, respectively. Whumpfs and shooting cracks were also observed at treeline and below. Over the last week, skiers were surprised by large avalanches; several were remotely triggered from a distance from low-angle or flat terrain. Expect increasing avalanche activity with the incoming warm weather.

Expect to find up to 20 cm of settled snow in wind-sheltered and shady areas. This snow covers wind-affected surfaces or a hard crust at upper elevations. The wind has scoured down west alpine slopes to a crust. A layer of weak, faceted crystals over a crust, or surface hoar, is the primary layer of concern, buried around 40 to 80 cm. This layer has been reactive, especially at treeline and below, over the last week.

A sun crust has formed on the surface on steep south and west-facing slopes, and snow is heavier and moist at lower elevations.

Thursday Night

Cloudy with 2 to 4 cm of new snow expected. 50 to 60 km/h southwest ridgetop wind. Treeline temperatures around 0 °C. Freezing level around 1500 m.

Friday

Mainly cloudy with no precipitation, 30 to 40 km/h southwest ridgetop wind. Treeline temperatures around +6 °C. Freezing level rising to 2500 m.

Saturday

Cloudy and sunny periods with no precipitation. 25 to 35 km/h southwest ridgetop wind. Treeline temperatures around +8 °C. Freezing level rising to 3000 m.

Sunday

Mix of sun and clouds with no precipitation, 40 to 50 km/h southwest ridgetop wind. Treeline temperatures around +6 °C. Freezing level around 2500 m.

More details can be found in the Mountain Weather Forecast.

• Avoid exposure to overhead avalanche terrain as temperatures increase.
• Persistent slabs have potential to pull back to lower angle terrain.
• As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.