What are floods? Floods are an overflowing of water
How are they formed? Floods are formed by heavy rain, snow melts, ocean waves and dams or levees failures.
Floods are formed when heavy rain falls over large bodies of water which would cause the large water bodies to overflow. Floods can also be formed when heavy rain falls over high areas that allows the water to flow down to the low areas.
A diagram of how a flood is formed by heavy rain
Floods can be formed when snow melt from global warming or rain. If ice breaks or melts it would release the water under it. And when the water is released, it would send huge chunks of ice into buildings and houses. This is called ice jam
Floods can be formed by dams or levees failures. Levees and dams are structures that prevent water from overflowing.
For how long do floods last? Floods can last for a day or a week or much longer
Are there some types of floods? yes, there are more than 5 types of floods and some of those types are:
1) River Floods. River floods occur from heavy rain, thunderstorms or snowmelt and ice jam.
2) Coastal Floods. This type of floods occur from heavy rainfall, high tides or wind currents. Coastal floods occur in places like Charleston, Georgia several times a year because the water level there is low. So when there is heavy rainfall, the water body overflows.
3) Storm surge. Surge floods is a dangerous rise in water level that is capable of flooding large coastal areas. It occurs from wind, waves, heavy rainfall and low atmosphere pressure.
4) Inland floods. This type of floods occur from heavy rainfall that causes dams and levees failures. For example, in 1999, in the United States, Hurricane Floyd and Tropical Storm Dennis caused a huge flood that caused $3 to $6 billion damage.
5) Flash Floods. This is the most common type of floods. It occurs from heavy rainfall that lasts for minutes or a few hours. It can also occur from dams and levees failures or ice jam. Flash floods occur quickly so they give people less time to react.
Is it possible to detect flash floods? Yes it is possible. Flash floods are usually associated with storms that can produce huge amounts of rain. Sometimes, the threat of a flash flood is overshadowed by another weather even going on at the same time so detecting remains a challenge.
Are there some tools used for detecting? If yes what are they? yes, there are some special tools used for detecting and some of them are:
1) Radars. A radars is a tool that can detect the amount of rainfall in a location. Radars display the precipitation data graphically on a map A radar can:
- show places of intense rainfall
- estimate the duration of rainfall (how long it would last)
- track the evolution of storm systems over time
- show existing storm cells intensify (show when storm cells become intense)
- show when storm cells begin to develop
- provide specific information about storm movements
- show the quality or ability of a flash flood threat
2) Rain Gauges. A rain gauge is a machine that shows the accurate measurement of rainfall and predicts flash floods.
3) Satellites. This is another tool that could be used for predicting floods, it is not as good as other tools, but it still shows some information. A satellite shows the complete coverage of floods and it have a small ability of detecting when a flood will arrive to areas.
What is forecasting and how can it help? Forecasting is the same as detecting. It is predicting floods. Hydrologists and meteorologists use radars, satellites and gauges to keep track of the amount of rainfall in an area. They store the information on computers to predict floods using the data they have.
How do floods affect people? Floods are one of the most dangerous natural disasters on earth. It takes 15cm of water to knock a human down and it takes 60cm of water to move a car. floods are capable of damaging roads and buildings, destroying crops and spreading diseases like typhoid, hepatitis and cholera.