Avalanche Canada ccampbell, Avalanche Canada

Sea to Sky Avalanche Forecast

Nov 20th, 2012 3:00PM

This bulletin is based on limited data. Local variations in conditions are likely to exist. Check out the forecasters blog for further details on interpreting early season bulletins here.



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Weather Forecast

On Wednesday expect moderate to heavy snowfall with freezing levels around 900m and light to moderate southerly winds. Things should dry out Wednesday night and into Thursday morning before a warm and wet Pacific frontal system makes landfall. Expect moderate to heavy precipitation Thursday afternoon and Friday with freezing levels spiking to 1800m or higher on Friday.

Avalanche Summary

Recent reports from the Whistler area include several natural avalanches up to size 1.5 primarily on north through east aspects, as well as widespread whumpfing associated with facets sitting on top of the rain crust from early November. Ongoing avalanche activity is expected in alpine during stormy periods.

Snowpack Summary

Total snowpack depths generally range from 60cm at treeline to 150cm in some alpine areas, while most areas below treeline are below threshold depths for avalanches. The main snowpack feature is a rain crust buried early November and now down around 80cm at treeline. A weak layer of facets sitting on top of this curst recently gave very easy  sudden collapse compression test results as well as moderate extended column test results that propagated across the entire column, in the Whistler area. Widespread whumpfing and cracking on this layer has also been reported. Because this weakness is so close to the ground in most areas, associated avalanche activity will likely be limited to slopes with smooth ground cover (e.g. scree slopes, rock slabs, summer firn, grass, etc.). For more information check out the telemarktips.com forum and the Mountain Conditions Report.

Valid until: Nov 21st, 2012 2:00PM