Hurricane Ida was so powerful, it reversed the flow of Mississippi River, experts say
Hurricane Ida’s destructive winds and storm surge reversed the flow of the Mississippi River in Louisiana on Sunday.
Ida was an “extremely dangerous” Category 4 hurricane when it made landfall Sunday afternoon in southeastern Louisiana. The storm tore through the area with extreme winds reaching maximum sustained speeds of 150 mph, catastrophic storm surge and heavy rain.
It was one of the most powerful hurricanes to ever hit the United States, the Associated Press reports.
Ricky Boyette, a spokesperson for the U.S. Army Corpse of Engineers, told the AP that Ida pushed in so much water from the Gulf of Mexico that engineers detected a negative flow in part of the Mississippi River.
A graphic from the U.S. Geological Survey showed the river’s discharge dropping as low as minus-39,900 cubic feet per second in Belle Chasse, Louisiana, early Sunday afternoon. Discharge refers to the volume of water flowing through a specific location along a river.
The river’s discharge at Belle Chasse, which is about 12 miles from New Orleans, remained negative between about 10:30 a.m. and 1:30 p.m., according to the USGS gauge.
“During that time, the flow of the river slowed from about 2 feet per second down to about half a foot per second in the other direction,” Scott Perrien, a supervising hydrologist with the USGS Lower Mississippi Gulf Water Science Center in Baton Rouge, told CNN.
Perrien told CNN that the gauge at Belle Chasse doesn’t measure the flow of the whole Mississippi River, so it’s possible that deeper parts of the river didn’t reverse direction.
Hurricane Ida hit Louisiana exactly 16 years after Hurricane Katrina.
On Aug. 29, 2005, Katrina made landfall near New Orleans as a Category 3 storm.
The storm, the costliest to ever impact the United States, devastated New Orleans and other areas within its path. It was one of the five deadliest hurricanes to hit the country — killing more than 1,800 people.
“Considering the scope of its impacts, Katrina was one of the most devastating natural disasters in United States history,” the National Weather Service says.
Perrien told CNN he remembers “off hand” that there was “some flow reversal” of the Mississippi during Katrina.
“But it is extremely uncommon,” Perrien told the outlet.
Downgraded to a tropical storm, Ida was located about 65 miles south-southwest of Jackson, Mississippi, with maximum sustained wind speeds of 45 mph as of 7 a.m. CDT Monday, according to the National Hurricane Center. It was moving north over southwestern Mississippi at 8 mph.
Tropical storm-force winds range from 39 to 73 mph.
Ida was continuing to bring dangerous storm surge and flash flooding to southeastern Louisiana and parts of Mississippi and Alabama on Monday, the NHC said at 7 a.m.
Tropical storm conditions are expected to continue over parts of Louisiana, southern Mississippi and southern Alabama through Monday morning or early afternoon.
This story was originally published August 30, 2021 at 9:40 AM with the headline "Hurricane Ida was so powerful, it reversed the flow of Mississippi River, experts say."
