I'm constantly harping on cat sailors to make sure their boats are well secured if the mast is left up, even if the weather looks mild. And recently here in Texas, we got to experience the "If you don't like the weather, wait 15 minutes..." phenomenon.
Below are links to the carnage that resulted this past Sunday morning when a big thunderstorm rolled through North Texas. While many of these boats were well-lashed to the trailers, the trailers were attached to nothing. Trailers/boats were tossed and even floated out from the beach... Several boats were totaled when they washed up again the dam (trailers still attached).
These pics are not pretty.
http://www.villagephotos.com/pubbrowse.asp?folder_id=1871037
http://www.flickr.com/photos/fleet23/sets/72157600318376489/
So you've been warned. Don't let this happen to you.
Brian C