Floods are one of the most common hazards in the United
States. Flood effects can be local, impacting a neighborhood or community, or
very large, affecting entire river basins and multiple states.
However, all floods are not alike. Some floods develop
slowly, sometimes over a period of days. But 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.
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
ground that appear harmless in dry weather can flood. Every state is at risk
from this hazard.
