Flood Facts

• Three types of flooding occur in North Carolina:

General River Flooding occurs after heavy rain has fallen over an extended period of time.  It usually occurs slowly enough to allow people and property to be moved to safety.  An extreme example of this is the flooding that occurred after Hurricane Floyd in September 1999.

Flash Flooding occurs very quickly and is always life threatening.  It happens more frequently in hilly or mountainous areas.  Rainfall of two to four inches in a couple of hours can result in a flash flood.  Dam failures also can result in flash flooding.

• Floods and Flash Floods can occur away from an area of heavy rain.  Especially in hilly or mountainous areas, rainfall that occurs upstream can result in flash floods downhill or downstream from where the heavier rain fell.  This happened in early January 1998 when up to 15 inches of rain fell of higher terrain in the mountains and caused major flash flooding in lower elevations.  People in Avery, Mitchell, and Yancey Counties reported a "wall of water" that ripped through several communities.

• Flash Floods are most common in the warm season due to thunderstorms dropping large amounts of rain in short periods of time.  Although hilly and mountainous terrain is especially prone to flash floods, even relatively flat areas can experience them.  Flash floods created by poor drainage and deep ponding of water on the roads occurred in May 1999 in Pamlico, Carteret, and Craven Counties when eastern areas of North Carolina received four to six inches of rain.

• General River and Urban Flooding was widespread over North Carolina during the late winter and early spring months of 1998.  Large rainfall amounts fell on ground already saturated by previous heavy rains causing heavy run-off into swollen rivers and streams.