Avalanche Forecast

WEDNESDAY NIGHT: Cloudy with snowfall, accumulation 15 to 20 cm, 20 km/h south wind, treeline temperature -6 C.

THURSDAY: Cloudy with snowfall, accumulation 10 to 15 cm, 50 km/h southwest wind, treeline temperature -1 C, freezing level rising to 1200 m.

FRIDAY: Early-morning snowfall then clearing skies, accumulation 50 to 80 cm, 50 km/h southwest wind, treeline temperature 0 C dropping to -5 C over the day, freezing level 1200 m dropping to 300 m over the day.

SATURDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 30 to 50 km/h southwest wind, treeline temperature -5 C.

We received reports of many natural and human-triggered avalanches over the past few days (e.g., here, here, here, and here). They all occurred within the recent 100+ cm of storm snow, with some propagating far, on the layers described in the Snowpack Summary.

Looking forward to Thursday, we anticipate that new storm slabs will be triggerable by riders at all elevations and on all aspects. The slabs will likely become more reactive as the day progresses as the freezing level rises and the snow switches to rain.

We'd appreciate any observations while you are out travelling on the Mountain Information Network.

Around 30 to 40 cm of snow is forecast for Wednesday night into Thursday, which will likely form new storm slabs in areas sheltered from the wind and wind slabs in exposed terrain. This snow will build on the 100+ cm of snow that has fallen since January 1. The snow will switch to rain above around 1200 m by the end of the day.

All of this snow overlies various old surfaces that formed during the cold spell in late December. They include a thin but hard melt-freeze crust or ice layer, weak and sugary faceted grains or feathery surface hoar in areas sheltered from the wind, or hard wind-affected surfaces in terrain exposed to the wind. There is uncertainty in how long it will take for all this snow to bond to these various surfaces.

The middle and base of the snowpack are strong, consisting of well-bonded snow and a few hard melt-freeze crusts.

• Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
• Watch for fresh storm slabs building throughout the day.
• Dial back your terrain choices if you are seeing more than 30 cm of new snow.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Continue to make conservative terrain choices while the storm snow settles and stabilizes.