Floods Floods are high water levels in a stream, lake, or ocean that can damage human facilities. Some floods can arrive suddenly and go away quickly when others can take days or months to build or get rid of. When floods occur in a place where people live, the large amounts of water can carry houses, bridges, cars, furniture and people. It can whip away trees and several other heavy items. What causes Floods? Sometimes when it rains more than a drainage can take, there can be floods. Even heavy rains can cause floods in a short amount of time. Rain that continues over a couple days or weeks can also create flooding. The pictures below are some examples on how storm drains look when they overflow. Storm drain overflow from rain Storm drain overflow from rain When rivers overflow they can also cause flooding. This happens when there is more water upstream, and as it flows downstream the water can spill over the bank and flood the area a...