Just an interesting little factoid I found today while looking for something else.
Did you know that Maricopa County (which includes most of the Greater Phoenix metro region) is one of the largest counties in the entire country?
Maricopa County covers 9,228 square miles! Within that are literally thousands of miles of land that are in a floodplain. Yep, floodplain. . . in the desert. (information courtesy of The Flood Control District of Maricopa County)
See pictures of Phoenix area monsoon flooding here and here
Read articles about the Phoenix area monsoons and the after effects here and find out when is monsoon season in Phoenix.