Evolution: A Journey Into Where We're From and Where We're Going. A coproduction of the WGBH/NOVA Science Unit and Clear Blue Sky Productions. Available online. URL: http://www.pbs.org/wgbh/evolu-tion/. Accessed October 10, 2008. Prother, Donald R. Bringing Fossils to Life: An Introduction to Paleobiology. New York: W. H. McGraw-Hill, 2004.
Stanley, Steven M. Earth and Life through Time. New York: W. H. Freeman, 1986.
flood A flood occurs when too much water is in one place at one time. When rains, heavy snow-melts, or combinations of these events bring more water than normal into populated areas, floods result. Many floods cause significant damage and destruction because over the past couple of centuries many cultures have moved large segments of their populations onto floodplains, the flat areas adjacent to rivers that naturally flood. Ancient cultures used these floods and the rich organic mud that covered the floodplains during the floods as natural fertilizers for farmlands. Now that many towns, cities, and other population centers have been built on floodplains, people regard these natural flood cycles as disasters. In fact, about 9 out of every 10 disaster proclamations by the president of the united states is for flood disasters, typically to provide funds to those who have built on flood-plains. Additionally, many types of natural vegetation have been removed from hillsides, particularly in urban areas. This reduces the amount of infiltration of water into the hillsides and increases the amount and rate of surface runoff, amplifying the danger of floods.
Floods come in many forms, including flash floods where huge volumes of water come rushing out of mountain canyons, carrying mud, boulders, and every other kind of debris washing into valleys and lowlands. some floods are associated with coastal storms that bring high tides into coastal lowlands and back up river systems far across deltas and coastal plains. Many regions experience slowly rising, long-lasting regional floods associated with spring snowmelts and unusually heavy rains that can last for weeks or months. some high-latitude climate zones also experience floods in association with the spring breakup of ice on rivers. As the ice melts, blocks move downriver, occasionally jamming and forming ice dams that can cause rapidly rising ice-cold floodwater to cover the river floodplains.
Was this article helpful?
Disasters: Why No ones Really 100 Safe. This is common knowledgethat disaster is everywhere. Its in the streets, its inside your campuses, and it can even be found inside your home. The question is not whether we are safe because no one is really THAT secure anymore but whether we can do something to lessen the odds of ever becoming a victim.