Man that brings back some old memories of when I was twenty something.There is a lake in north Louisiana called Ivan lake.They used to say the same thing about that place,I always figured it was just guys pulling my leg.Now that you've mentioned the same thing happening somewhere else,there maybe more to it than I thought.Every year when they said the lake was turning over,I'd think "yeah-right,good one,ha,ha".
That's the same way it was explained to me,so yeah,I've heard of it-just didn't believe it until now.