How do flood waters work?
Most of the damage caused by floods, whether from people drowning or from property loss, is due to the force of water. You've probably enjoyed a peaceful time swimming in the ocean or a river without being knocked off your feet. So how can two feet (61 centimeters) of flood waters wash away a car and six inches (15 cm) knock you over? The difference is the amount of pressure in flood waters.
In a flood, lots of water collects in one place, while there's little (if any) water in another area. Since water always tries to "find its own level," it gushes quickly from where it’s gathered to where there's less of it. Flash floods in particular move very quickly, uprooting trees, cars and even houses. Extra water from storms, heavy rains, hurricanes, or the breaking of a dam can cause flooding. Take flood warnings seriously and always try to get out of the path of a flood.