Stormy weather continues, bringing extreme winds and up to 120 mm of precipitation as rain or snow by Monday afternoon.
Travel in avalanche terrain is not recommended.
A crust / facet layer from mid-November was buried 50 to 120 cm deep before this storm. This layer has been especially reactive on wind-loaded, northerly features. Storm slabs could step down to this layer.
60 to 120 mm of precipitation combined with strong southerly winds is continuing to build widespread thick and reactive storm slabs above the rain/snow line.
Wet loose avalanches may be possible where the snow surface is moist or wet.
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 current storm is expected to greatly increase the likelihood of both natural and human-triggered avalanches.
60 to 120 mm of precipitation, combined with strong to extreme southerly winds, is forecast to fall by 4 pm Monday. This is adding to the 20 to 40 mm that fell on Sunday. We expect to see widespread reactive storm slabs building as a result.
The snow/rain line elevation is uncertain and expected to fluctuate during the storm. It's possible we could see rain up to 2100 m. There is potential for wet loose avalanches where the snow surface is wet.
A crust with facets, formed in mid-November, was buried 60-120 cm, depending on the aspect, before the storm. Storm slabs have the potential to step down to this layer, causing very large avalanches.
The snowpack rapidly diminishes below 1200 m.
Sunday Night
Cloudy. 30 to 60 mm of precipitation as snow or rain at treeline. 40 km/h south ridgetop wind. Treeline temperature 1 °C. Freezing level 1900 - 2200 m.
Monday
Cloudy. 40 to 60 mm of rain at treeline. 60 km/h southridgetop wind. Treeline temperature 3 °C. Freezing level between 2100 - 2400 m.
Tuesday
Cloudy. 15 to 25 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1000 - 1400 m.
Wednesday
Mostly cloudy. 20 to 30 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -6 °C. Freezing level 1000 m.
More details can be found in the Mountain Weather Forecast.
