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
The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the ...
(NWS) when weather conditions are favorable for very heavy
rain that could cause flooding or
flash flooding.
A watch does not mean that flooding is occurring, only that
weather
Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the t ...
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 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
A flash flood watch ( SAME code: FFA; also referred as a "green box" by meteorologists) is severe weather watch product of the National Weather Service that is issued when conditions are favorable for flash flooding in flood-prone areas, usually ...
, which indicates rainfall amounts that ''could'' produce flooding are expected, has basically the same meaning as a flood watch.
In
Australia, the
Bureau of Meteorology
The Bureau of Meteorology (BOM or BoM) is an executive agency of the Australian Government responsible for providing weather services to Australia and surrounding areas. It was established in 1906 under the Meteorology Act, and brought together ...
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 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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