Why are Ski Resorts so liberal?

[Alcibiades]

As others have mentioned, Democratic strength essentially comes from a combination of affluent liberals attracted by the cosmopolitan atmosphere of the resorts, and the workers, who are usually young people with something of a countercultural streak (similar to the classic Democratic group found in lots of big cities of young service workers, often well-educated but low-earning).

The interesting question, though, is why this seems to be something of an exclusively (North) American phenomenon. Certainly I know that in Switzerland, ski resorts often don't vote any differently from other rural conservative villages.