Flood alerts are issued by weather agencies to alert residents that
flood conditions are a possibility.
Types of flood alerts in the United States
In the
United States, a
flash flood watch is issued by the
National Weather Service (NWS) when weather conditions are favorable for very heavy
rain that could cause flooding or
flash flood
A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice or snow flowing o ...
ing.
A watch does not mean that flooding is occurring, only that
weather conditions have created or will create a significant risk for it. If flooding occurs, a
flood warning
A flood warning is closely linked to the task of flood forecasting. The distinction between the two is that the outcome of flood forecasting is a set of forecast time-profiles of channel flows or river levels at various locations, while "flood wa ...
or
flash flood warning
A flash flood warning ( SAME code: FFW) is an hazardous weather statement issued by national weather forecasting agencies throughout the world to alert the public that a flash flood is imminent or occurring in the warned area. A flash flood is a ...
would be issued and immediate action should be taken. A flood warning or flash flood warning is issued when flooding is imminent or already occurring. When flood warnings are issued, it means that area
waterways will likely soon be in flood. Not all flood watches suggest that large-scale flooding, such as during
landfalling tropical cyclones, is possible.
Flood alerts in other countries
In
Canada, a
heavy rainfall warning, which indicates rainfall amounts that ''could'' produce flooding are expected, has basically the same meaning as a flood watch.
In
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, the
Bureau of Meteorology issues a flood watch that covers similar conditions to Flood Watches in the United States. However, they are known by slightly different names in some areas.
In Europe, there is the
European Flood Awareness System
The European Flood Awareness System is a European Commission initiative to increase preparedness for riverine floods across Europe.
The disastrous floods in Elbe and Danube rivers in 2002 confronted the European Commission with non-coherent fl ...
and the commercial product including app and data services
FloodAlert.
See also
*
Flood forecasting Flood forecasting is the use of forecasted precipitation and streamflow data in rainfall-runoff and streamflow routing models to forecast flow rates and water levels for periods ranging from a few hours to days ahead, depending on the size of the ...
References
Weather warnings and advisories
Flood control
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