ABOVE Hurricane Isabel destroyed Jimmy Morris ' clam hatchery on the Core Sound at Sea Level. 

 TOP RlLjHT Hans Paerl, UNC-CH Institute of Marine Sciences, takes post-hurricane water samples from the 

 Pamlico Sound. BOTTOA 1 RlL]HT: Larry Crowder and students sample, sort and size fish during research cruises 

 on the Pamlico days after Isabel. B07TOA4 LLFT: Houses on Hatteras Island took a beating from the storm surge. 



BOTTOM RlLjHT: Nacie Pcele recalls storms from decades ago that came calling on Hatteras Village. 



Cape Lookout area, Pietrafesa says. 



To determine where and when the surge 

 would hit, the scientists used the computing power 

 of two different systems. One computer model 

 even showed the potential forflooding along the 

 Pamlico and AlbemaHe sounds as well as the 

 Chesapeake Bay. 



Isabel did exactly what their computer models 

 predicted, Pietrafesa says. 



In spite of the warnings of ocean and 

 sound-side surge, many residents did not evacuate. 

 Pietrafesa thinks that many let theirguards down 

 when Isabel was reclassified as a Category 2 as she 

 approached land. 



But with 1 05 miles per hour winds and a 

 storm surge of 1 2 feet, a Category 2 storm packs a 

 powerful punch. Swirling winds push ocean water 

 toward the shore. The advancing surge combines 

 with the normal tides to create the hurricane storm 

 tide, which increases the mean water level. In addi- 

 tion, wind waves are superimposed on the storm 

 tide — a condition that produced 25-foot waves 

 along parts of the Outer Banks. 



Isabel made landfall just after high tide. 

 When the storm tide coincides with the normal 

 high tides, the rise in water level can cause severe 

 flooding in low-lying coastal areas. 



Though hurricane season officially ended 

 Dec. 1, university and weather service researchers 

 continue to analyze ocean data from Hurricane Isa- 



bel, factor in atmospheric influences, and attempt 

 to understand the anatomy of a hurricane. 



Hurricanes are a fact of life for North Carolina, 

 Pietrafesa says. They draw energy from warm tropi- 

 cal ocean waters to power intense winds and ocean 

 surges, he explains. And, more often than not, the 

 warm Gulf Stream delivers the storm and all its 

 destructive force to North Carolina's doorstep. 



Some day, Pietrafesa says, prediction will be 

 so precise that emergency managers will be able to 

 narrow evacuation to city-block scale. 



A^easuring the Damage 



Meanwhile, other researchers are measuring 

 the damage wrought by Hurricane Isabel as she cut 

 a path through North Carolina, Virginia, Maryland 

 and Pennsylvania. Before she finally blew herself out, 

 she had claimed 54 lives and chalked up $2 billion 

 in property damage. 



According to Spencer Rogers, North Carolina 

 Sea Grant coastal erosion specialist, Hurricane 

 Isabel will be the most documented hurricane ever. 



"The state took the initiative and requested 

 the Federal Emergency Management Agency to put 

 together a Hurricane Isabel Rapid Response task 

 force," he explains. "In the past, we did a good job 

 in documenting individual case studies. But this 

 was a chance to broaden post-storm evaluation to 

 a community scale, looking at water, wave, erosion 

 and wind." 



Before the high-water marks dried, the team 

 of scientists and coastal engineers spread out along 

 the Outer Banks and sites on the Pamlico Sound to 

 conduct a post-storm survey of damage to coastal 

 buildings. Rogers was asked to help plan and imple- 

 ment the survey since he is familiar with the evolu- 

 tion of building codes over the past three decades. 



North Carolina has the second oldest hur- 

 ricane-resistant building code in the country, he ex- 

 plains. Since being implemented in the mid-1960s, 

 it was reinforced by the N.C Floodplain Manage- 

 ment Program and Coastal Area Management Act 



'The survey was an opportunity to test the 

 performance of existing building codes, and check 

 to see if and under what conditions they are or 

 aren't working," he says. 



"In this storm, we clearly took a significant 

 step backwards," Rogers says. 



To his surprise, newer buildings experienced 

 more damage than older ones. Since the late 1 960s, 

 typical beach homes have been built on deep piling 

 foundations, with the lowest floor elevated. The 

 open space accommodates parking and allows 

 water to wash through dunng storm events. 



More recently, there has been a shift to 

 low-elevation building, with enclosed, under-the- 

 house living space. Consequently, Spencer observed 

 new oceanfront homes with bottom-story rooms 

 pounded apart by 25-foot waves and storm surge. 



Other data collected will be useful for resource 



14 WINTER 2004 



