The Setting

There are 6,251 miles of tidally influenced shoreline in South and North Carolina, consisting of a long chain of barrier islands, including the Outer Banks, and extensive salt marshes and tidal freshwater marshes that have formed behind these barrier islands. About two-thirds of South Carolina's coast is part of the "Sea Island Coastal Region," an area that is characterized by wide expanses of salt marsh punctuated by numerous inlets, sounds, and bays. North Carolina contains one of the largest and most productive aquatic systems in North America -- the Albemarle-Pamlico Sound. Together the Albemarle-Pamlico Sound and the Sea Island Coastal Region provide critical nursery areas for more than 75 species of fish and shellfish.

Both commercial and recreational fisheries are important elements of the Carolinas' coastal economy, and the coastal region also supports a vibrant tourist economy. Like many of the nation's coastal regions, the Carolinas has had a tremendous residential and commercial investment in coastal areas during the past 10 years. Meanwhile, the decline of living marine resource species, changes in biodiversity, and degradation of habitats are just a few of the indications that these human activities are posing serious threats to the region's coastal and marine ecosystems.

The rapid population growth and development in vulnerable coastal locations has led to the populace in the region becoming increasingly at risk to naturally occurring, extreme environmental events. Over the past 100 years, North Carolina has experienced more direct hurricane strikes than any other Atlantic coast state except Florida. South Carolina ranks third (Landreneau, 2001). Furthermore, since 1886, there have been 951 tropical cyclones that have been recorded in the Atlantic Ocean and the Gulf of Mexico. Approximately 166, or 17.5%, of those tropical cyclones passed within 300 miles of the Carolinas. Some of these storms have wreaked terrible damage. Hurricane Floyd, which hit in 1999, was a monstrous flood producer that is now recognized as the greatest disaster in North Carolina history. Hurricane Hugo, which struck the South Carolina coast in September 1989, caused $7 billion in damages. The storm surge was extreme, reaching nearly 20 feet -- the highest ever recorded on the East Coast -- at Bull's Bay, just north of Charleston. Nationally, most (83%) of the damage associated with tropical cyclones is due to the winds of category 3, 4, and 5 hurricanes. Alternatively, in North Carolina categories 2 and 3 hurricanes have been the most damaging (73%), because of flooding across the broad flat coastal plain in addition to winds. This may be true for South Carolina as well.

In addition to hurricanes, mid-latitude or extra-tropical cyclones develop rapidly off the coast of the Carolinas throughout the winter season (Cione, et al., 1993). Extra-tropical cyclones often cover larger areas (700 -1000 miles across) than the largest hurricanes or typhoons. These storms, many of which are very rapidly intensifying "bombs," form over water with central barometric pressure decreasing rapidly and generating very high winds. During 47 winter months between the years 1982-1990, 116 extratropical storm events were documented off the Carolinas (Cione, et al., 1993). The paucity of offshore weather observations on the Carolinas' coast results in a lag in detection behind rapidly occurring storm development, often in excess of 15 to 25 hours. This delay shortens the time available for communities to respond to high winds, heavy precipitation, and subsequent coastal, estuary/inland flooding.

Such examples clearly illustrate the profound effects that coastal system processes have on the safety, economics, and stability of communities residing and visiting the Carolinas' coastal regions. A comprehensive coastal ocean observing system that serves to inform the public of coastal conditions and is utilized to enhance the accuracy and timeliness of hazard predictions is long overdue.

References

Landreneau , D. 2001. Atlantic tropical storms and hurricanes affecting the united states: 1899-2000* *NOAA Technical Memorandum NWS SR-206, National Weather Service Office Lake Charles, LA.

Cione, J., S. Raman, and L. Pietrafesa. 1993. The Effect of Gulf Stream-induced Baroclinicity on U.S. East Coast Winter Cyclones. Mon. Weather Rev. 21(2):421-430