Avalanche Forecast

Moderate - Uncertainty is due to the limited number of field observations.

Wednesday night: Cloudy, convective flurries with up to 5 cm of snow, light southwest wind, freezing level dropping to 300 m. 

Thursday: Cloudy, isolated convective flurries with trace accumulations, light southwest wind, alpine temperatures near -11 C, freezing level around 500 m.

Friday: Cloudy, 5-10 cm of snow with an intense storm moving in overnight, southwest winds increasing to strong by end of day, alpine temperatures rising to -6 C, freezing level rising to 600 m.

Saturday: Cloudy, 30-50 cm of snow expected to accumulate by mid-morning, strong southwest wind, alpine temperatures rising to -4 C overnight during heaviest precipitation and dropping through the day, freezing level rising to 1000m and dropping to 500 m by end of day.

On Wednesday, there was a report of isolated small (size 1) wind slabs releasing on a melt-freeze crust on north and northeast aspects above 2000 m.

On Tuesday, operators reported a large (size 2.5) cornice result as a result of explosive work. 

Earlier in the week, small (size 1-1.5) natural and human triggered loose dry and soft slab avalanches were observed releasing in recent snow.

At upper elevations, a total of 15-25 cm of snow has accumulated in the past week over a substantial crust that formed during the last big rain event. A thin crust from a brief warm-up on Tuesday can be found within this snow. Strong west and southwest winds have redistributed available snow into dense wind slabs in wind-exposed areas. These wind slabs may be reactive to human triggering in immediate lee terrain features (for example, just down-wind of ridges), particularly where the snow is not well-bonded to the buried crust.

We have a lot of uncertainty about the composition and reactivity of this widespread crust interface. There have been reports of both surface hoar and facets above the crust. As snow gradually accumulates and settles into a cohesive layer above it, we are vigilantly tracking this layer ahead of the incoming weekend storm. Send us your observations of what is above the crust where you are travelling using the Mountain Information Network. 

Average snow depths vary drastically with elevation, with over 400 cm in the alpine, 150-200 cm at treeline, and a drastic drop to below the threshold for avalanches below treeline. Deeper crust layers buried early season have transitioned to dormant.

• Be alert to conditions that change with elevation and wind exposure.
• Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
• Caution around slopes that are exposed to cornices overhead.