One of the many programs of the Flood Control District is educating Maricopa County residents about flooding and flood hazards in an effort to promote flood safety. Newcomers to the County are often surprised to learn the desert holds an immense potential for flooding. In fact, in its history Maricopa County has experienced numerous major floods that have caused millions of dollars of damage.
Over the years, the District has implemented flood control structures, facilities and management plans that have significantly reduced the severity of flooding in the County. Nevertheless, it is important for residents to be aware of the history of flooding in the County and why flooding occurs.
Beware of Flash Floods
A flash flood is a rapidly moving flood through low-lying areas such as washes and canyons. Flash floods occur after intense thunderstorms that drop large amounts of rainfall in a short period of time. When this happens, the ground cannot absorb the water fast enough so it accumulates in channels and flows downhill. Flash floods are often preceded by a debris flow that contains rocks, brush, logs and anything else it picks up along the way. This initial debris flow can be anywhere from one foot to 10 or more feet in height.
Many times a flash flood occurs where no rain has fallen in the immediate area. In the desert Southwest, this situation can become very hazardous to people engaged in outdoor activities such as hiking and off-roading, and to the motoring public in general. Flash floods are very dangerous because they happen quickly and often without warning. Areas that have a potential for flash flooding should be avoided when thunderstorms are nearby. A vehicle is not a safe refuge during a flash flood. Fifty percent of flash flood fatalities occur when drivers try to cross flooded washes. Do not try to cross a roadway covered by floodwaters – the flood may conceal damage to the roadway beneath. Just two feet of water can cause even a large truck or SUV to float. Find an alternate route or wait it out. Most flash floods dissipate in an hour or so. In 2006, the National Weather Service reported 59 deaths in the United States due to flash floods, the third highest in weather-related deaths, surpassed only by heat and tornadoes.
David Rankin of Rankin Studio has captured some amazing videos of flash flooding in Arizona and Utah. Please take some time to view this spectacular footage to gain a better understanding of what you might be up against if you are caught in a flash flood. Click on the video images to play.