What is the most common type of flooding in the United States?

The National Flood Insurance Program (NFIP) says the most common type of flooding is called overbank flooding.  Overbank flooding occurs when downstream channels receive more rain or snowmelt from the watershed than normal, or a channel is blocked by an ice jam or debris.  Overbank flooding varies with the watershed’s size and terrine.  One measure of a flood is the speed of its moving water.  Hilly and mountainous areas have faster moving water.  There is a greater hazard to people and property when water is moving fast.  Water does not move as fast on flat terrain. For more information about the NFIP and floods go to Flood Insurance