A storm is expected to bring strong winds and up to 65 mm of precipitation as rain or snow on Sunday.
Travel in avalanche terrain is not recommended.
A crust / facet layer from mid-November is buried 50 to 120 cm deep. This layer has been especially reactive on wind-loaded, northerly features. Storm slabs in motion may step down to this layer resulting in very large avalanches.
Wet loose avalanches may be possible if the snow surface is moist or wet, especially during periods of rain.
35 to 60 mm of precipitation combined with strong southerly winds is forecast to build reactive storm slabs overnight and throughout Sunday.
Numerous size 1 to 2.5 explosive, natural and human-triggered slabs and cornices were triggered in the Whistler/ Blackcomb area last week. A few of these slabs stepped down to the mid-November crust up to 1 m deep, setting off very large avalanches. Most of these avalanches released in high alpine leeward north through east facing features.
The incoming storm is expected to greatly increase the likelihood of both natural and human-triggered avalanches.
35 to 65 mm of precipitation, combined with strong southerly winds, is forecast to fall by 4 pm Sunday. The snow/rain line elevation is uncertain and likely to fluctuate during the storm. There is potential for wet loose avalanches where the snow surface is wet. In the alpine, we expect to see reactive new storm slabs building as the new snow adds up.
A crust with facets, formed in mid-November, is buried around 60-120 cm, depending on the aspect. Storm slabs have the potential to step down to this layer.
The snowpack rapidly diminishes below 1200 m.
Saturday Night
Cloudy. 5 to 20 mm of precipitation as snow or rain at treeline. 50 km/h south ridgetop wind. Treeline temperature 2 °C. Freezing level between 1900 - 2100 m.
Sunday
Cloudy. 30 to 45 mm of precipitation as snow or rain at treeline. 60 km/h south ridgetop wind. Treeline temperature 1 °C. Freezing level between 2000 - 1600 m.
Monday
Cloudy. 60 to 100 mm of precipitation as rain or snow at treeline. 50 km/h south ridgetop wind. Treeline temperature 3 °C. Freezing level between 1500 - 2500 m.
Tuesday
Mostly cloudy. 20 to 35 cm of snow. 40 km/h south ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 m.
More details can be found in the Mountain Weather Forecast.
