Hurricane Harvey pummeled the Houston area with an unprecedented four feet of rain, making it the most extreme rain event in U.S. history. Cars and houses are underwater, and thousands of people have needed or await rescue. The event has been called a “500-year flood”- a flood event that has a one-in-500 chance of occurring in any given year in that location. Residents in 500-year flood zones aren’t required to purchase flood insurance, even though there is more than a 5 percent chance, more than one in 20, of a 500-year flood over a 30-year mortgage.
Source: Watertown Daily Times