Sorry for the late reply to my own thread!
Uh, let's see here... ok, first of all, I'm coming from North Van not Whistler. It's back country skiing that I do and we had been out on the Coquihalla the day before. Conditions are quite a bit different out there versus the Howe Sound corridors. Significant packed snow doesn't even start until several hundred feet above sea level out on the Coq. That probably explains how surprised I was when I ran into that wall of snow at the Powerhouse Channel the next day. Anyway, I'm thinking of testing CandT's point about them plowing the road for a slide. Anyone know how to make one of those?
Armytruck, on the successful day I mentioned, I was fly fishing the whole time. Just swinging flesh patterns and Christmas Trees through seams in the deeper trough trenches that you can find along the sides of the river. Everybody liked the xmas trees, but only the dollies/bulls seemed to go for the flesh patterns. (I was actually looking for those late coho that showed up in early December.) Depth was the key. I had to get it right down to the bottom and do the 3-inch strip through the seam. The bows were all feisty 16-inchers... lots of leaping and running all over the place. The dollies/bulls were ranging from 4 - 9 lbs I figure and were a lot of fun as well. There was actually ice out that day too. It built out well into the seams' slower waters. At one particularly good spot there must have been a 10' x 20' shelf almost an inch thick. Once hooked, the fish all seemed to try and hide under it which I found really interesting. It basically meant grounding themselves in shallow water that they would otherwise never go near. After the third fish turned himself into a shim between the ice and gravel, I decided to smash it all and send it downstream.
Last point I should add is that the road past the Powerhouse Channel seems to have some plow history to it. That is, you can see the banks of plowed snow from previous dumps built up underneath the fresh stuff. I'm taking this as a hopeful sign that they will plow again soon. The last couple of days have laid down another 10cm on that road!