Why it is in news?
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India has been designated as a nodal centre for preparing flash-flood forecasts by the World Meteorological Organization (WMO).
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That means India will have to develop a customised model that can issue advance warning of floods in Vietnam, Sri Lanka, Myanmar and Thailand.
All about flash flood
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A flash flood is a rapid flooding of geomorphic low-lying areas: washes, rivers, dry lakes and basins.
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Caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields.
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May occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam.
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Flash floods are distinguished from regular floods by having a timescale of less than six hours.
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Occurs when it rains rapidly on saturated soil or dry soil that has poor absorption ability.
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Significant examples-
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2013: Uttarakhand, Uttarakhand, India: 822 dead
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2014: Srinagar, Jammu & Kashmir, India: approximately 300 dead.
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2016: September 20, Garut Regency in Indonesia floods: 33 dead
Six hours before
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IMD would be working to customise a weather model, developed by the United States and donated to the WMO, to warn of flash floods at least six hours in advance.
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A test version of this was being tried out by the IMD, and that was able to give a flood warning about an hour in advance.
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Using a combination of satellite mapping and ground-based observation, this system ”” called the Flash Flood Guidance System ”” aims to provide forecasts six hours in advance.
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Like India, several Southeast Asian countries depend on the monsoon and are prone to its vagaries.
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The proposed model would provide forecasts by computing the likelihood of rainfall and the soil moisture levels to warn of possible floods.
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Though Pakistan was among the list of countries that would benefit from the forecast, it had refused to participate in the scheme.
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While the science to warn of floods could be developed, India was yet to work out how exactly it would warn countries of potential inundation.
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India currently has a warning system for tsunamis that also doubles up a warning system for several Asian countries.
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The Central Water Commission, which monitors India’s dams, warns of rising water levels in the reservoirs, which are usually taken to be signs of imminent floods.
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The organisation has recently tied up with Google to develop a software application to visualise rising water levels during heavy rains.
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The WMO says flash floods account for 85% of flooding incidents across the world, causing some 5,000 deaths each year.
Source
The Hindu,Wikipedia