Hurricane Laura's storm surge of more than 17 feet among highest recorded in Louisiana
A tremendous wall of seawater taller than 17 feet that moved ashore with Hurricane Laura, sweeping some Cameron Parish homes off their foundations, appears to be one of the highest storm surges ever recorded in Louisiana.
Like other major hurricanes in recent decades, Laura's massive storm surge caused such destruction that it's difficult for researchers with the National Hurricane Center and other federal agencies to get exact estimates.
"If you get a really big storm surge, it destroys everything," said Jamie Rhome, a storm surge specialist at the Hurricane Center who oversees the storm surge program for the National Weather Service. Sometimes no homes are left standing.
But several research teams from the hurricane center, the weather service and the U.S. Geological Survey have been following Laura's trail in Cameron Parish searching for clues in the devastation.
"We have three pieces of evidence of a greater than 17 feet storm surge," Rhome said. But, he added, "no one may ever know how high it was."
The National Weather Service reported an above ground level mark of 17.2 feet, he said. "The USGS got a similar mark of 17.1 above ground level. And, a separate weather service crew got a measure of 16.6 in that same area, about 2-2.5 miles inland near Grand Chenier."
The storm surge model has been run in a hindcast for comparison, he said, and it "suggested the peak is still another couple of feet higher, there's just nothing there to find the evidence."
The findings underscore the accuracy of the hurricane center's September 26 forecast, which warned Laura could bring "unsurvivable" storm surge of 15 to 20 feet in Cameron Parish, where the storm was projected to make landfall.
That forecast had warned the exact height of the storm's surge would depend on where the storm made landfall and whether the landfall coincided with high tide.
The findings also illustrate how a landfall in more heavily populated areas to the east or west could have caused even greater destruction, said Hal Needham, an independent storm surge researcher and founder of U-surge, an organization that provides coastal flood date and analysis.
State and local government officials breathed sighs of relief that the surge wasn't higher along the Calcasieu River. Early estimates put the surge in Cameron Parish at around nine feet, but storm specialists said the surge was more severe in areas east of the storm's eye, in less inhabited parts of the coast.
Hurricane Laura's surge among highest recorded on Gulf Coast
Laura's surge also is among some of the highest surge ever to be recorded in the Gulf of Mexico, behind Katrina, Camille and Carla. Both Katrina and Camille struck Pass Christian, Mississippi. Katrina's peak surge was measured at 27.8 in 2005 and Camille's at 24 feet in 1969. Hurricane Carla's surge was 22 feet in Port Lavaca, Texas in 1961.
Needham, who was on the ground doing field surveys after Laura, said his research shows a surge of about 18.89 feet at Rutherford Beach in Cameron Parish. If you account for the water's normal level in the weather service's 17.2-foot mark, he said, that puts the storm surge at around 18.89 feet.
That's a few inches higher than the 18.7 he measured from Hurricane Katrina's surge in St. Bernard Parish, he said.
"It's historic," Needham said. "It's a tremendous amount of water. That will really be unbelievably destructive because not only are you putting almost 19 feet of salt water above normal, but it's usually moving very fast so it can really destroy houses or really anything that's in its way."
Researchers go into the field and look for debris lines, for example, high water marks inside a home. If homes aren't left standing, it makes it very difficult, Rhome said. When a surge rises above 15 feet, it causes near total destruction, he said. Often, measuring instruments, such as tide gauges and portable observing stations, also are destroyed.
In the case of the 17.2 measurement by the weather service, it was inside a home on stilts at Rutherford Beach.
"To get a mark that high is pretty rare," he said. "I've been in this job 12 years and I don't think I've seen a high water mark that high in my time."
Forecast estimates of surge 'pretty good,' with worst in uninhabited areas
Needham said he was on the ground in southwest Louisiana within days of Hurricane Laura's landfall.
The research findings show the federal government's predictions were "pretty good," despite the idea among some in the public that forecasters overestimated the potential surge, Needham said. In reality, it seems the surge just hit more uninhabited areas.
"Nonetheless, it was a destructive surge," Needham said. "The silver lining here is that it happened in a more rural area."
A few lucky things happened to keep the storm surge from devastating parts of southwest Louisiana, he said. The biggest was the location of landfall. If the storm had moved 50 miles to the west, Lake Charles — as well as parts of Texas — could have been in the path of severe surge.
"That would have put a lot more water out toward Lake Charles, maybe even Beaumont and Port Arthur," Needham said. "The big surge only moved across the coastal prairie there for the most part."
Another factor was the storm's speed. Hurricane Laura was a fairly fast storm, moving out of the area quickly, which prevented the surge from moving too far inland.
Needham, based in Galveston, Texas, said that level of storm surge could have devastated populated areas. Galveston is the location of the deadliest natural disaster in U.S. history — a hurricane called the Great Galveston Storm of 1900 — where more than 6,000 died.
That storm, Needham said, had a surge of about 16 feet.
"Literally every building was just flattened. All you could see was a debris field," Needham said. "That surge was slightly less than Laura's. Really, if you had a densely populated town or city there without any protection, it would've been incredibly destructive."