The avalanche danger is rated as EXTREME at all elevations.
It may decrease below treeline as the snowpack is washed away by the rain. At this time travel in the mountains is not recommended. Even the traditional safe routes through the valley bottoms may be at risk from large avalanches initiating in start zones high above at the peaks.
On Whistler Mountain at the 1650 metre study plot, the precipitation so far during the storm has been about 150 mm. Half of that amount has been rain to at least the Peak elevation (2180 metres), and possibly higher. MOT avalanche techs report that in the Duffey Lake area, the precipitation has fallen as snow above about 2000 metres. When the dust finally settles from this storm, it may go down as one of the ugliest winter weather events on record.
But on a more positive note, the snowpack weaknesses that developed during the cold weather should be eradicated they will either be rained away or destroyed by natural avalanching. As we have already seen numerous times this winter, temperatures will cool, a crust will form, and the snowpack development can start over once again.
The weather forecast is calling for a break in the precipitation late Thursday through Friday, but it is scheduled to kick in again for the weekend. Check for the most current avalanche bulletins before you rush out into the backcountry. Call 604-938-7676 for conditions outside the Whistler-Blackcomb boundaries or surf the CAA website for conditions around the province.
Remember that in Canada, most avalanche fatalities occur after the storm abates when the danger rating drops down into the considerable category.