Hurricane season has only just begun, but a storm is brewing in the Gulf of Mexico that could test New Orleans’ river levee system.
An advisory from the National Hurricane Center at 4 a.m. on Thursday morning projected a low-end hurricane, called “Barry,” could make landfall as early as Saturday, bringing with it heavy winds and more than 20 inches of rain across Louisiana’s Southeast.
Forecasters haven’t yet declared the storm a depression. The storm is said to remain on the low end if it develops into a hurricane, but its impacts could still be particularly damaging to parts of the state due to the current height of the Mississippi River.
The river is considered to be at “high water” when it reaches 8 feet above sea level, which usually occurs in winter or spring and ends in June. But this year, the Mississippi River rose to high water in November and has yet to come down.
Flooding from the river has been ongoing since January—now the longest flood in history—that could be compounded by rain from the tropical depression and its storm surge upon landing.
What is the levee system?
Louisiana has two types of levees in place. One protects the coast from ocean storm surges, and the other keeps the Mississippi River on its course to both prevent flooding and confine the flow of the water.
In 2005, when Hurricane Katrina hit the state, the storm surge levees failed, as floodwaters submerged much of New Orleans, including the Lower 9th Ward. Hundreds of people in the Lower 9th Ward were killed. Homes, commercial buildings, and infrastructure were destroyed. The city was 80% flooded following the breach of the storm surge levees.
With 15 to 20 inches of rain expected this weekend in addition to the tropical storm, Louisiana’s river levee system will be put to the test.
Can the Mississippi River flood?
It’s possible, especially in areas of Louisiana where the river levees aren’t as high, some experts say. On the other hand, officials with the Army Corps of Engineers have said that overtopping won’t likely occur. In 2009, a federal judge declared the Army Corps responsible for the destruction of most of New Orleans during Hurricane Katrina.
Forecasters with the National Weather Service projected 10-20 inches of rainfall in Southern Louisiana. With that level of rainfall “you can get anywhere from moderate to major flooding on rivers,” Mike Efferson, a meteorologist with the NWS in New Orleans and Baton Rouge told Fortune.
Parts of New Orleans saw several inches of flooding early Wednesday morning caused by severe thunderstorms just days ahead of the tropical storm. “The pumps are prepared for one inch of rainfall the first hour, and half an inch every hour thereafter,” said Efferson. “And we got beyond what the pumps can do.”
Efferson added that the river could be cresting by Friday night around midnight local time.
With that in mind, locals worry the river levees aren’t high enough in some areas. In New Orleans’s Bywater neighborhood, the Lower 9th Ward, Algiers, and St. Bernard Parish, some levees are between 18 and 20 feet high, according to a database compiled by the Army Corps of Engineers, which was reported by the New Orleans Advocate Wednesday.
The levees could be overtopped by flooding from the river; however, Corps officials say the risk for levee failure is slim.
“We’re confident with the integrity,” Corps spokesman Ricky Boyett told The New Orleans Advocate. “The levees are extremely robust and designed to handle a lot of pressure.”
Officials later disputed the information on their database and stated the levees were higher than previously reported.
The Army Corps of Engineers could not be reached for comment.
Are cities prepared to deal with the impacts of global warming?
Human-induced climate change is causing a change in hurricane behavior, and will likely lead to more events like what is currently happening in Louisiana — that is, extreme weather overlapping.
“This combination of river flooding and flooding from cyclones or hurricane, and storm surge are worse, more frequent, and more intense than in the past,” Brenda Ekwurzel, the director of climate science at the Union of Concerned Scientists told Fortune. Ekwurzel added that it is expected to get worse.
There are currently more than 950,000 people at risk of coastal flooding in Louisiana with another 262,000 projected to be at risk by 2050. The human and economic toll of extreme weather is increasing. In the past 40 years, officials estimate that extreme weather has resulted in nearly 10,000 deaths, though that number is likely higher. Eight of the 20 costliest climate disasters since 1980 occurred over the course of just eight years.
Experts say it’s imperative to build resilient infrastructure for the climate disasters we’re seeing presently, while also preparing for the future.
“If you’re not designing or upgrading infrastructure with an honest assessment of human-induced climate change in the U.S., then you can be underprepared,” said Ekwurzel.
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