Floods are one of the most common hazards in the United States. Flooding can be local, impacting a neighborhood or community, or larger, affecting entire river basins and multiple states. However, all floods are not alike. Some floods develop slowly, sometimes over a period of days and weeks. But other kinds of flooding known as flash floods can develop quickly, sometimes in just a few minutes and without any visible signs of rain. Flash floods often have a dangerous wall of roaring water that carries rocks, mud, and other debris and can sweep away most things in its path. Overland flooding occurs outside a defined river or stream, such as when a levee is breached, but still can be destructive. Flooding can also occur when a dam breaks, producing effects similar to flash floods. Just a few inches of water from a flood can cause tens of thousands of dollars in damage. Each year, more deaths occur due to flooding than from any other severe weather related hazard.
Be aware of flood hazards no matter where you live, but especially if you live in a low-lying area, near water or downstream from a dam. Even very small streams, gullies, creeks, culverts, dry streambeds, or low-lying area that may appear harmless in dry weather can flood. Every state is at risk from this hazard.
For more information, see FEMA’s flood web page.