What causes a flood?

Floods are most often caused by intense rainfall over a short period of time, prolonged heavy rain, a dam or levee failure, or a sudden release of water held by an ice or debris jam. Most flooding conditions are associated with seasonal weather. Floods can be caused by melting snow combined with rain in the winter and early spring, severe thunderstorms in the spring and summer, and hurricanes in the summer and fall. However, any source of water can potentially cause a flood.

Source: NOAA and NWS