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| Sunday, 30 January 2005 |
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Junior Observer |  |
| News Business Features Editorial
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Floods : When water becomes the destroyer
Floods have enough power to change the course of rivers and bury houses and buildings under mud. Flash floods are the most dangerous kind of all floods, because they combine the destructive power of a flood with incredible speed and unpredictability. A flood can be defined as a general and temporary condition of partial or complete flooding of normally dry land area from an overflow of inland or tidal waters, unusual and rapid accumulation or runoff of surface waters from any source or a mudflow. The collapse or subsidence (sinking) of land along the shore of a lake (or similar body of water) due to erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels, results in a flood. Floods can be slow, or fast rising, but generally develop over a period of days. Humans have been experiencing floods ever since the start of the agricultural revolution, when people built the first permanent settlements on the great riverbanks of Asia and Africa. Seasonal floods deliver valuable topsoil and nutrients to farmland and bring life to otherwise infertile regions of the world such as the Nile River Valley. Flash floods and large 100-year floods, on the other hand, are responsible for more deaths than tornadoes or hurricanes. Flood water is responsible for massive losses in property damaged annually. What causes floods? Flooded areas usually start off as very dry land. Floods are caused by heavy rains that pour too much water into rivers and other waterways, making these natural channels unable to carry all the water. Rising water flows over or breaks the banks of the waterways, causing the surrounding land to be flooded. Other causes of floods can be the melting of large snow masses or tidal waves. Where do floods occur? The type of land that is prone to flooding is broad and flat, usually situated on the banks of a river or main waterway. There are three different types of flooding; one - the water comes off the mountains eroding the beds and banks of the river as it flows; two - the river travels through broad valleys, which slows the current of the river down. If the current is slow, it will transport less material down the river; three - flood-plain type. What is a flash flood ? A flash flood is the fastest-moving type of flood. It happens when heavy rain collects in a stream or gully, turning the normally calm area into an instant rushing current. The quick change from calm to raging river is what catches people off guard, making flash floods very dangerous. Any flood involves water rising and overflowing its normal path. But a flash flood is a specific type of flood that appears and moves quickly across the land, with little warning that it's coming.
Dam failures can create the worst flash floods. When a dam or levee breaks, a gigantic quantity of water is suddenly let loose downstream, destroying everything in its path. Flash flood waters move at very fast speeds. They have the power to move boulders, tear out trees, destroy buildings, and obliterate bridges. The walls of water can reach heights of 10 to 20 feet and generally carry a huge amount of debris with them. Be prepared It is no secret that, if there was an early warning, many lives could have been saved from the deadly tsunami that attacked our country. Therefore, as children, you should make it a habit to be prepared for such circumstances in the future. Keeping track of the weather forecast can help keep you safe. So don't forget to check the weather forecast daily. The best response to any signs of flash flooding is to move immediately to a higher ground. A flash flood doesn't call ahead and let you know it's coming. You need to protect yourself by tracking the weather and being alert to danger. Flash floods occur when heavy rain falls in an area. When forecasters predict storms, stay away from streams, ditches and gullies. A storm upstream from you could send water rushing down your way. **** Act immediately If a flash flood warning has been issued for your area, act immediately! You may only have seconds before flood waters appear. Try to keep yourself and others out of danger. If you are outdoors and a flash flood is likely, get to higher ground immediately! Get out of places that are likely to flood, like canyons, ditches and dry stream beds. Avoid already flooded areas. Never attempt to cross flood water. If you're in a vehicle during a flood, never drive through flooded roadways! |
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Floods are the most common and widespread of all weather-related
natural disasters in the world. Countries in Asia such as Sri Lanka,
India, Bangladesh, Indonesia and Cambodia and even Western countries such
as England are frequently affected by this natural phenomenon. Communities
in the North East of Sri Lanka experienced severe flooding recently soon
after the tsunami disaster.
Many things can cause a flash flood. Generally, they are the result of
heavy rainfall concentrated over one area. Most flash flooding is caused
by slow-moving thunderstorms, thunderstorms that repeatedly move over the
same area, or heavy rains from hurricanes and tropical storms.
