FILE - Louisiana weather

National Weather Service radar image of Southern Louisiana.

Louisiana may be hit with 10 to 15 inches of rain over 24 hours starting Friday, possibly leading to overflowing levees and severe flooding in a state already dealing with flash floods and an elevated Mississippi River, Gov. John Bel Edwards warned Wednesday.

There is a 90 percent chance a low-pressure storm system will develop in the Gulf of Mexico over the next two days, according to the National Weather Service. While it may not develop into a named storm, that doesn’t mean residents should take it lightly, Edwards said.

“You only have to go back to 2016 to remember exactly how dangerous and catastrophic unnamed storms can be,” he said. “We all need to take this very, very seriously.”

In August 2016, the greater Baton Rouge area absorbed 20 to 30 inches of rain over three days, causing floods that claimed 13 lives and damaged more than 50,000 structures. Much like that rain event, the current storm in the Gulf appears to be moving very slowly, which could lead to extended heavy rain in certain areas.

The expected storm also complicates the “river flood fight,” Edwards said. Storm surges near the mouth of the Mississippi River could reach up to three to four feet, and there could be a “considerable amount of overtopping” of levees in Plaquemines Parish. Local officials in Plaquemines currently are considering their options, which could include evacuations, he said.

“Right now, we believe that any overtopping of the levees will be relatively short duration of about 12 hours, but that is still a very, very significant hazard,” Edwards said. “We’re not sure whether the state will be opening any shelters yet.”

The National Guard, FEMA and various state agencies are moving into threatened areas, he said. The Coastal Protection and Restoration Authority is monitoring floodgates along the Mississippi; some already have been closed and others are likely to be closed soon.

The governor plans to declare a statewide emergency Wednesday and may seek a federal declaration before the storm arrives.

“We don’t know yet where this storm is going to land, but we know it’s going to be a big storm,” he said.

The New Orleans area already saw flash flooding and at least one tornado Wednesday morning from a storm unrelated to the system in the Gulf. Edwards said this weekend’s storm could bring significant wind, warning that it doesn’t take much wind to knock over trees when the ground is wet.

The governor urged anyone not already prepared for severe weather to begin doing so, mentioning getagameplan.org as a source of information. Another media briefing is planned for midday Thursday.

Reporter

David Jacobs is a Baton Rouge-based award-winning journalist who has written about government, politics, business and culture in Louisiana for almost 15 years. He joined The Center Square in 2018.