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An analysis by a national nonprofit found that 11,000 homes in the Carolinas were flooded due to rising sea levels.
More than 11,000 homes in the Carolinas experienced storm surge flooding during Hurricane Florence as a result of rising sea levels over the past five decades, according to data scientists with First Street Foundation, a national sea-level research nonprofit.
The hurricane’s storm surge “impacted over 51,000 homes by pushing water over 25 percent or more of each property,” the analysis says. Roughly 20 percent, or 11,000, of those would not have been affected had the same storm hit in 1970, when sea levels along the Carolinas were 6 inches lower.
Researchers arrived at those numbers by determining maximum storm surge elevations through an analysis of tidal and river gauge data from the National Oceanic and Atmospheric Administration and the United States Geological Survey. They then compared that data with elevation data from NOAA, USGS, the federal Department of Agriculture and local sources, and identified as “impacted” any areas where storm surge heights were higher than land elevations.
“Higher sea levels cause greater storm surge, as there is more water available for hurricanes to push onto land, and that additional water removes friction that would otherwise slow the surge,” the analysis says. “The conservative models used in this research show that increases in sea level rise result in an additional 23 percent relative increase in storm surge.”
Increased development along the coast also impacted the area’s risk of damage, researchers said.
“Since the 1970’s, much of the region’s wetlands, farms, and conserved areas have been developed for urban use,” the report says. “Many of the homes built in these areas were impacted by Hurricane Florence’s storm surge.”
Only 23,000 homes would have been impacted by Florence’s storm surge in 1970, compared with 51,000 today, according to the data.
The report also found that at the sea level projected for 2050 by the U.S. Army Corps of Engineers—roughly 15 inches above current levels—an additional 102,000 homes would have been affected by the observed storm surge from Hurricane Florence.
“With sea levels and coastal development on the rise, the impacts of hurricane storm surge will only get worse,” said Matthew Eby, the foundation’s executive director. “The time to rethink America’s sea level rise and adaptation strategy is now.”
Kate Elizabeth Queram is a Staff Correspondent for Government Executive’s Route Fifty and is based in Washington, D.C.