SEA 



SCIENCE 



TOP: The Wright Brothers made their historic flight at Kitty Hawk. 

 BOTTOM: This NC ECONet weather station in Raleigh is one of many across the state. 



T3 



JL^efore the Wright Brothers took off 

 on Dec. 17, 1903, the air was bitterly cold — 8 

 degrees with the chill factor, according to Wright 

 Brothers National Memorial historian Darrell 

 Collins. 



"There also was a nor'easter that morning 

 with winds blowing from 27 to 30 miles per 

 hour," Collins says. 



With the steady winds tearing down the 

 coast, the brothers made history at Kitty Hawk 

 with the first sustained flight in the air. 



What caused the windy conditions in 

 December? 



There was probably a low-pressure system 

 in the area, according to Len Pietrafesa, director of 

 external affairs in the College of Physical and 

 Mathematical Sciences at North Carolina State 

 University. 



"December, January and February are the 

 most active months for nor'easters on the Outer 

 Banks," adds Pietrafesa, a former North Carolina 

 Sea Grant researcher. "During a nor'easter, winds 

 can get up to 70 mph." 



Throughout the year, windy conditions are 

 commonplace along the Outer Banks. 



One reason for the high winds is the large 

 amount of water around the area, including the 

 Albemarle-Pamlico Estuarine System — the 

 second largest estuary in the United States. 



When wind hits land, the friction of trees and 

 vegetation usually slows it down, says Pietrafesa. 



"However, the barrier islands are so narrow 

 that the wind field doesn't recognize them as 

 land," he adds. "The wind is generally 1 1/2 times 

 to 2 1/2 times larger in magnitude on the Outer 

 Banks than on the western side of the Pamlico 

 Sound." 



During December 1999, the maximum wind 

 speed at Cape Hatteras was 41 mph compared to 

 20 mph at Castle Hayne near Wilmington, which 

 is only a mile from the ocean, according to the 

 National Weather Service. 



Wind speed doubles as it blows from land to 

 the ocean, says state climatologist Sethu Raman. 

 The reverse happens when wind blows from 

 ocean to land, decreasing the speed by half as it 

 reaches land. 



"The wind stress — what creates the lift and 

 forces an airplane up — is also 2 1/2 to 6 times 

 larger at the Outer Banks than on the mainland," 



24 WINTER 2003 



