The Flood Plain Concept

For John, BLUF:  It is all a crap shoot.  Nothing to see here; just move along.

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It’s Time To Ditch The Concept Of ‘100-Year Floods’

This is from The Five-Thirty-Eight Blog, by senior science writer Maggie Koerth-Baker, on 30 August 2017.

A nice, brisk, discussion of the concept of the 100-year flood plain.

The thing about the 100-Year Flood Plain is that it does not mean a flood every one hundred years, but rather a 1% chance of a flood each year.  That means that if you are unlucky (you avoid the tables in Las Vegas or Mohegan Sun) you could have a "hundred year flood" twice in two years.  It isn't some sort of mathematical evil, it is just statistics.

Regards  —  Cliff