High Quality Content by WIKIPEDIA articles! Arizona has been affected by hurricanes on numerous occasions. Usually, these storms originate in the eastern Pacific Ocean, make landfall in the Mexican states of Baja California or Sonora, and dissipate before crossing into the United States. Thus, in most cases, it is only the tropical cyclones` remnant moisture that produces heavy rainfall—and in some occasions, flooding—in portions of Arizona. However, approximately every five years, a tropical cyclone retains sufficient strength to enter the state as a tropical storm or a tropical depression. Arizonans can expect indirect flash floods caused by the remnants of tropical cyclones to occur about every two years.