What is SFHA and the “100-year Floodplain”?
The SFHA is also known as the 100-year floodplain. It is more precisely defined as the floodplain associated with a flood that has a 1-percent annual chance of being equaled or exceeded in any given year. Therefore the SFHA is not a flood that happens once in a hundred years, rather, it is a flood that has a one percent chance of occurring every year. Thus, the 100-year flood could occur more than once in a relatively short period of time.
