Yes, you really can spend your summer vacation skiing. Sounds a little odd at first, but when you think about it it all makes excellent sense. And no, you don't have to go south of the equator to find snow in summer. What you do have to do though is go to altitude.
What they do is run summer camps on Mount Hood in Oregon. You can train up and polish you skills for there is indeed snow all summer there.
As to it making sense, well, you get to go skiing on snow (obviously the point) but you don't have to put up with that appalling, cold, winter weather. Sounds like a deal all round really.