Flooding

Floods are one of the most common hazards in the United States and may occur during any month of the year in Louisiana. A flood is defined when water overflows onto normally dry land. Not all floods are alike; they happen on different scales of space and time. The main types of floods are:

Flash Floods

Flash floods can occur within a few minutes or hours of heavy rainfall or from a dam or levee failure. These floods can destroy structures, down trees, roll boulders, and create new waterways.

Urban Floods

Floods can be magnified in urban areas. As land is converted from fields and woodlands to roads and parking lots, it loses its ability to absorb rainfall. During periods of urban flooding, streets can become swift moving rivers.

River Floods

Flat areas near rivers, streams, lakes, and reservoirs are vulnerable to river floods. Some river floods occur when winter or spring rains fill river basins with too much water too quickly. Other floods can happen when storm systems move slowly or from heavy rains from hurricanes or tropical systems.

Area Floods

Area floods are long-lived and do not usually threaten life. Standing water in flat areas, such as an open field, is just one example of an area flood. Area floods can cause damage to crops and cause livestock to become displaced. Also, the standing water from this type of flooding can serve as a breeding ground for insects and diseases.

Source: NASA.gov

Did You Know?

Flooding events in Louisiana have been caused by the remnants of tropical storms and hurricanes, and before Hurricane Katrina, storms like Hurricane Audrey in 1957 and Hurricane Betsy in 1965 caused significant flooding across portions of the state. The direct and indirect impacts of heavy rains from convective storms and low-pressure systems have caused flooding along the Mississippi River Basin, including in floods in 1927, 1937, 1973 and 2019. You can learn more about some of these events through NOAA’s Flood Safety page for Louisiana.