A flood forms when it has been raining for a long period of time, a dam or levee breaks, or when there is more water that can be held in a stream or river and the water breaks over into the surrounding regions called flood plains.
Floods occur when the volume of water contained by the shores of a body of water or the banks of a waterway exceeds the body's capacity, or when their is to much rain to be contained by a other body of water.
Flash floods- A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and basins. It may be caused by heavy rain with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields.
Flash floods may occur after the collapse of a natural ice or debris dam, or even a human structure such as a man-made dam.
The Burchardi flood- this flood was a storm tide that struck the North Sea coast of north Frisia and Dithmarchen on the night between 11 and 12 October 1634. it shattered the coastline and caused thousands of deaths. 8,000 to 15,000 people drowned. No people prepared for this flood.
The Hatfield Flood- this flood was in San Diego, United States, in 1916. it destroyed the Sweetwater and Lower Otay Dams, and caused 22 deaths and $4.5 million in damages. people prepared for this flood by getting far away as possible.