What Is a Regional Flood?

Regional floods affect a large geographic area, such as a multi-county or multi-state region. They cause widespread property damage and can result in large death tolls.

Local flooding occurs in relatively small geographic areas, for example, a few streets in a city, or a single town. A flash flood is an example of a local flood, according to the National Weather Service.

Regional floods normally occur on a seasonal basis when winter and spring rains combine with melting snow to overfill river basins and flood the banks. They also occur during periods of excessive rain when the rain saturates the soil and the runoff overflows streams and rivers, states the Thinkquest Library.

According to the National Weather Service, the March 1936 New England regional flood resulted in more than 150 deaths and property damage of $300 million. Heavy rains and melting snow pack inundated the still frozen ground causing increased runoff into the Connecticut River causing multiple river basins to reach peak stage.

Multiple counties or states form flood districts to address the problem of regional floods under a partnership approach. These flood control districts plan for and respond to floods in their area. Examples include the Clark County Regional Flood Control District in Las Vegas, NV and the Harris County Flood Control District in Houston, TX.

Flood control districts, state emergency planning offices and the Federal Emergency Management Agency plan for and respond to regional floods, often in concert. Each individual can also plan for regional floods by creating a family emergency plan using the templates on the FEMA Web site and by purchasing flood insurance.