What starts floods?

Floods are caused by an overflow of water that submerges land that is usually dry. The most common cause of flooding is heavy rainfall or the rapid melting of snow resulting in water levels in bodies of water such as rivers or lakes rising, overflowing and spilling onto surrounding land. Other causes include:

* Dam failure: A dam is a structure that is built to hold back water. If a dam fails, the water can be released suddenly and cause a flood.

* Levee failure: A levee is a bank of earth or other material that is built to prevent water from overflowing. If a levee fails, the water can flood the area behind it.

* Coastal storm: A coastal storm is a storm that occurs over the ocean. These storms can cause high waves and flooding along the coast.

* Landslide: A landslide is a mass of earth, rocks, and debris that slides down a slope. Landslides can block rivers or streams and cause flooding.

* Ice jams: Ice jams occur when pieces of ice block a river or stream. This can cause water to back up and flood the surrounding area.