Laura’s coastal cost assessed from air
NEW ORLEANS — Hurricane Laura was hardly done ripping across Louisiana before scientists started combing through satellite imagery and drone footage and preparing to survey coastal areas to see what damage was caused by the monster storm.
Southwest Louisiana's gulf coast is a fragile yet vibrant region, home to important fisheries, petrochemical plants and small communities of people who live at the water's edge. But numerous factors have contributed over the decades to erosion, which can be exacerbated by hurricanes. Some key takeaways of the immediate analysis of Laura's effects have emerged:
I will take months to know effects
Scientists say some coastal impact from Hurricane Laura is inevitable. Pounding waves can tear at the marshes that make up most of the coast, and storm surge can inundate wetland areas, depositing sand and sediment in places that didn't have so much before.
Laura certainly moved things around, but it could take months to figure out if the hurricane caused any significant and permanent land loss.
Bren Haase, who heads the state's Coastal Protection and Restoration Authority, said the eastern Cameron shoreline "got pounded pretty hard." But they haven't been able to measure what has happened yet. In the western parts of Cameron Parish, where the shoreline is more sandy beach, many homes were badly damaged and helping people recover is the top priority, but the beach itself seemed to have fared well, he said.
Kara Doran, an oceanographer with the U.S. Geological Survey, said about 70% of the coastline from from Gilchrist, Texas, to Pecan Island, Louisiana — about 125 miles — had overwash. That means sand was transported landward, covering as much as 165 yards of marsh. "There was a tremendous amount of water flowing over that area," Doran said.
But it will take months to assess whether all that water and sand leads to permanent land loss, said Brady Couvillion, also of USGS. Initial satellite imagery showed extensive flooding, much of which got trapped and hasn't receded. The question is what lies beneath.
"Once those flood waters recede, that area may have converted to open water or it may go back to a marsh condition and that's what's going to take some time to assess," he said.
Did the wetlands protect the coast?
One of the benefits of having a vibrant coastal wetlands, scientists argue, is that it provides a natural buffer that can reduce the power of a hurricane's storm surge before it hits inland areas where more people live. Laura took a slight jog to the East just before making landfall which probably prevented some of the worst storm surge from pushing all the way into Lake Charles.
Naomi Yoder, from Healthy Gulf, which advocates for environmental causes along the coast, believes the wetlands in Cameron and Vermilion parishes also lessened the impact of the storm surge in some areas.
Yoder said it's important not to minimize the damage in places like Lake Charles where the hurricane's howling winds badly damaged homes and businesses. But she said it helped people in the area to have large swathes of intact wetlands take the brunt of the storm, in places including the Rockefeller Wildlife Refuge and the Sabine National Wildlife Refuge.