Flooding
Floods are one of the most common hazards in the United States and may occur during any month of the year in Iowa. 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:
Source: Weather.gov
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.
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.
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 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.
Did You Know?
Floods across the state are most frequent in June, which has the highest average rainfall of any month (4.64 inches). One of the most destructive floods on record for the state occurred during the Summer of 1993 when the Mississippi River topped its banks after weeks of rainfall. You can learn more about this event at this link.