Suppose Lake Michigan Overflows?

Early in the film Some Like it Hot there is a scene in a speakeasy which is about to be raided. Tony Curtis is teasing Jack Lemmon for being worried, he rattles off a list of bad things that could happen but obviously would not happen.

As the movie was made in 1959 but took place in 1929 the joke was that Tony Curtis’ list of things that wouldn’t happen actually did end up happening.
Joe: Suppose the Stock Market crashes? Suppose Mary Pickford leaves Douglas Fairbanks? Suppose the Dodgers leave Brooklyn? Suppose Lake Michigan overflows?
I’ve never understood the reference about Lake Michigan. Was there a famous flood in Chicago between 1929 and 1959? What is this line in reference to?

They may have been referring to this “tidal wave” that hit Lake Michigan’s
shores in 1954…

http://www.kacm.com/Tidalwave.htm