A flash flood is a sudden and intense flood that occurs in a short period of time. It is usually caused by heavy rainfall or a rapid melting of snow. The term 'FRESHET' is used to describe a sudden rise in the level of a river or stream due to heavy rain or melting snow. A 'SPATE' is a sudden and large increase in the amount of water flowing in a river or stream. Both FRESHET and SPATE are terms used to describe flash floods.