‘The 100-year standard refers to a flood that has a one percent chance of being exceeded in any given year. It does not refer to a flood that occurs ‘once every 100 years’. In fact, for a home in a 100-year flood zone there is a greater than 26% chance that it will see at least one 100-year flood over a period of 30 years (and, similarly, more than a 74% chance over 100 years).’
