Buy a metal detector on your credit card, save the box and return it once you've found the ski. Works great, I've done it myself. The ski cannot be under the snow more than a foot or 2 for the metal detector to reliably work. You should dig around the area of the lost ski, downhill of course, if you think it is "six or 8 feet under the snow" as some people have said. Most likely though, the ski is within six inches of the top surface if it ran far enough that you cannot find it. When skis are deep under the snow they usually don't get far since the snow is too dense down there. Set up a grid and go to work. You'll find it, they don't just disappear...usually.
I would like to bring up the fact that powder cords are referred to as "beater cords" at Alta and I'm sure other places in the West. Only beaters and tourists use them. That said, there have been several times over the past 3 years at Alta that I wished I had cords on my skis. But they're not cool to have so of course I don't use them. Pretty silly if you ask me.