Floods can be classified as sudden floods and, the most known, is overflowing of rivers. The sudden floods generally cause more deaths and, river overflowing cause loss of properties.
A sudden flood is produced when runoff coming from a high precipitation provokes a increase of flow in streams which are normally dry. These kind of floods most common in zones with dry weather and rocky terrain. In this case, there is no soil or vegetation on the surface to decrease the effect of excessive rainfall.
River overflowing is more common in big rivers located in zones with humid climate. In this case, the excess of runoff caused by storms last longer.
Floods can also be caused by the accumulation of ice in a river or because of high tides. However, most floods can be related to a storm.