The three most common types are riverine, coastal, and shallow.
Riverine flooding is when a channel receives too much water, the excess flows over its banks and into and the adjacent floodplain. Coastal flooding is caused by hurricanes and severe storms. High winds and changes in air pressure push water toward the shore causing a storm surge. Shallow flooding occurs in flat areas where a lack of channels means water cannot drain away easily. For more information about the NFIP and floods go to Flood Insurance .