Letters to the Editor 19076 Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Science News June 19, 2002 at 12:13 pm Regarding this article, as planes fly low over the bay to land at San Francisco airport, wing vortices frequently bend down and become twin waterspouts that last up to 20 seconds. Dave GrossmanPalo Alto, Calif. Share this:EmailFacebookTwitterPinterestPocketRedditPrint