Vadel is an old term for turns that are linked together in one continuous motion. I was commonly done by an exaggerated wiggle of the hips, counter rotating with the shoulders. A straight line down is taken down the hill and the shoulders would be square to the hill no matter which way the skis would be pointing. It can be a real blast when you get going in a groove. I does need a flat terrain, bumps just mess up your rhythm. By the way have you ever taken a kayak down a sledding hill? I just thought about this the other day.....
For the kayaking down a ski hill part of this conversation... Although I have never done it, I believe Franz Obermeyer and a couple of his friends did this in backcountry areas on Warren Miller's Ride movie. It is truly amazing to watch, and if you own a kayak, you should definitly try it.
I have never kayaked down a mountain, but I do want to try it, lol, I will start small though with an old boat, not my new fiberglass. Plastic would be the way to go! Have you done it?