The original Bay St. Louis bridge, once connecting neighboring cities Pass Christian and Bay St. Louis, was catastrophically damaged by Hurricane Katrina. A new bridge was built and opened almost two years after the storm in May of 2007.

Rising sea levels have cost home values over $263 million in Mississippi with the hardest hit areas located along the Gulf Coast – including Bay St. Louis, Pass Christian, Kiln and several other nearby towns and cities. 

“In Bay St. Louis the average impacted home would be worth 49 percent more if tidal flooding were not a risk, and in Kiln 41 percent more,” said Steven McAlpine, Head of Data Science at First Street Foundation. “These are the hardest hit neighborhoods in Mississippi because homes and roads at low elevations and sea level rising is increasing the frequency of flooding along Jourdan River.”

In a report published Dec. 3, First Street Foundation – a nonprofit that studies flood risk in the U.S. – examined sea levels and flooding from 2005 to 2017. The organization’s new work also includes a tool, Flood iQ, that lets Gulf Coast residents look up their address to see exactly how much value their home has lost. The tool also includes forecasts for how much more value homes may lose in the next 15 years.

“Qualitatively, it’s understanding that neighborhoods start to get these reputations for being flooded areas,” said Dr. Jeremy Porter, the study’s co-author and a professor at Columbia University. “They’re areas where school buses can’t get to, with people not being able to get to their jobs.”

McAlpine and Porter examined millions of real estate records and tens of thousands of tidal gauge readings to inform their findings. Using high-precision data, they could see exactly where flood water landed on roads and properties. They then — after controlling for various factors including the local housing market, the economic recession, and disasters like Hurricane Katrina and the Deepwater Horizon oil spill — compared how those properties sold to homes that didn’t have flood risks. 

Research from the tech non-profit First Street Foundation.

The research duo said road flooding had a higher impact than home flooding because of transportation effects and the debris left on streets.

In October, school buses in Bay St. Louis struggled to reach certain areas because of flooded roads, WLOX reported.

When asked if she was surprised by the findings, Dr. Wei Wu, an associate professor of Landscape Ecology at The University of Southern Mississippi, said “not really.”

“We have known that sea-level rise will negatively affect natural ecosystems and human communities,” Wu said via e-mail. “It is not just sea level rise, but also the acceleration of sea level rise (increase of the sea level rise rate) that has and will have impact on flooding in the future people may not expect based on their previous experience.

“This study clearly shows climate change and sea level rise are affecting us right now, not 50 years later.”

Mark Cumbest, who in June finished a 13-year stint as Chairman of the Mississippi Real Estate Commission and has ran his own realty company in Moss Point for over 40 years, said he hadn’t heard of home values dropping due to flooding, but that flood insurance can be a concern.

“I have not (seen) evidence that the rising sea level has had any effect, that I’ve been able to see yet, on the real estate market,” Cumbest said. “The issue that we’re dealing with year in and year out is the flood insurance availability and flood insurance costs.”

He said uncertainty around the National Flood Insurance Program, specifically while it awaits Congress’ reauthorization, can create nervousness for lenders and disrupt the housing market.

As far as sea levels rising, though, Cumbest, a seventh generation Jackson County resident, wasn’t aware of the issue, and was skeptical about whether global warming is a real issue.

“I have not been convinced yet that global warming is a threat,” he said, noting that he hadn’t seen the report yet.

Research from the tech non-profit First Street Foundation.


He added that he witnessed some homes losing value during the study period, but he attributed that to the Deepwater Horizon oil spill.

“I can’t attribute any damage, so far, to the (rising sea levels),” Cumbest said.

While populations in flood-prone areas increased in the United States overall between 2000 and 2016, Mississippi’s coastal populations decreased, according to an analysis from; Harrison County lost the most people with a -9.3 percent change.

The counties’ populations just north of the coast, however, have increased in that same time: George (+26.1 percent), Stone (+26.2 percent), and Pearl River (+12.1 percent).

Wu was skeptical that this trend will continue, however, and said she was concerned about the number of residents in Mississippi’s Gulf Coast.

“We are not sure whether the declining trend (of Gulf Coast populations) will continue,” she said. “Worldwide, people are attracted to coastal regions. People in coastal regions, their properties, and their mental and physical health are vulnerable to increased flooding hazards due to sea level rise and frequent tropical cyclones. We are very concerned about this.”

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Alex Rozier, from New York City, is Mississippi Today’s data and environment reporter. His work has appeared in the Boston Globe, Open Secrets, and on In 2019, Alex was a grantee through the Pulitzer Center’s Connected Coastlines program, which supported his coverage around the impact of climate change on Mississippi fisheries.