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<br /> <br /> <br /> <br />Hurricane Dennis followed <br />an unusual path, approaching <br />the coast, retreating to about <br />150 miles offshore, meandering <br />offshore for several days, <br />approaching the shore again, <br />and eventually moving across <br />North Carolina during Septem- <br />ber4-5 in a west-northwesterly <br />direction over the Neuse and <br />Tar-Pamlico River Basins <br />(fig. 2). Rainfall amounts were <br />generally greatest near the <br />coast, but exceeded 7 inches in <br />much of the central Neuse and <br />Tar-Pamlico River Basins <br />(table I; fig. 3). <br />Hurricane Floyd made land- <br />fall near Cape Fear on <br />September 15 with the center of <br />the stonn traveling to the east of <br />Wilmington (fig, 2). The stonn <br />moved in a north-northeasterly <br />direction over the lower Cape <br />Fear, Neuse, Tar-Pamlico, <br />lower Roanoke, and Chowan <br />River Basins. The stonn <br />delivered 12 to 18 inches of rain <br />to much of the Neuse and Tar- <br />Pamlico River Basins (table I; <br />fig. 4), triggering regional <br />flooding that continued <br />throughout the remainder of <br />September and most of <br />October. <br />Hurricane Irene never made <br />landfall in North Carolina, but moved <br />in a northeasterly direction just east of <br />the coastline on October 17 (fig, 2). <br />However, rainfall amounts associated <br />with Hurricane Irene exceeded 5 <br />inches in the eastern part of the Neuse <br />Basin and in the central and eastern <br />Tar-Pamlico Basin (table I). The addi- <br />tional rainfall from Hurricane Irene <br />coupled with the already-saturated soil <br />and elevated river levels ensured that <br />the Tar and Neuse Rivers remained <br />above National Weather Service <br /> <br />Figure 2. Satellite image of eastern North Carolina with generalized basin outlines and tracks <br />for Hurricanes Dennis, Floyd, and Irene, September-October1999, (Satellite Image from <br />National Aeronautics and Space Administration, 1999,) Flooding along selected rivers, such as <br />the Tar, Neuse, and Waccamaw, can be seen, as well as sediment plumes in Albemarle Sound <br />and the Pamlico River. <br /> <br />(NWS) flood stage throughout most of <br />September and October. <br /> <br />any particular year, The I DO-year, <br />12-hour rainfall for eastern North <br />Carolina is between 7 and 8 inches <br />(Hershfield, 1961), This means that a <br />rain event that lasts 12 consecutive <br />hours and delivers at least between 7 <br />and 8 inches of rainfall has a I-percent <br />chance of occurring during any given <br />year in eastern North Carolina. Like- <br />wise, the 1 DO-year, 24-hour rainfall for <br />eastern North Carolina is between 8 <br />and 9 inches (Hershfield, 1961). Rain- <br />fall amounts associated with more rare <br />events (for example, SOD-year stonns) <br /> <br />Hurricane Floyd Rainfall <br />Recurrence Intervals <br /> <br />Extremely large rain events are <br />characterized by (I) the duration ofthe <br />rain event, (2) the magnitude of the <br />rainfall for a selected duration, and <br />(3) the recurrence interval, or the <br />chance that a rain event of a specified <br />duration and magnitude will occur in <br /> <br />Two Months of Flooding in Eastern North Carolina, September-October 1999 <br />