A flood is the inundation of normally dry land by an overflow of water, resulting from heavy rainfall, overflowing rivers, rapid snowmelt, storm surges, or dam failures. Floods are the most common natural disaster.

Floods are the most common natural disaster, and they vary in type, duration, and location. They can be slow-developing events lasting days or weeks, or sudden, rapid "flash floods" that pose significant dangers.

A natural disaster is the name of any natural hazard associated with a natural hazard such as floods, tornadoes, hurricanes, volcanoes, earthquakes, or catastrophes that affect the environment in such a way that causes natural resources, financial and loss of life.