Hurricane Ida was powerful enough to reverse flow of Mississippi River

Winds from the violent storm in Louisiana reached 150 mph.

Monisha Ravisetti
Monisha Ravisetti Former Science Writer
Monisha Ravisetti was a science writer at CNET. She covered climate change, space rockets, mathematical puzzles, dinosaur bones, black holes, supernovas, and sometimes, the drama of philosophical thought experiments. Previously, she was a science reporter with a startup publication called The Academic Times, and before that, was an immunology researcher at Weill Cornell Medical Center in New York. She graduated from New York University in 2018 with a B.A. in philosophy, physics and chemistry. When she's not at her desk, she's trying (and failing) to raise her online chess rating. Her favorite movies are Dunkirk and Marcel the Shell with Shoes On.
2 min read

NOAA satellite imagery of Hurricane Ida on Sunday. 


Sixteen years after Hurricane Katrina ravaged Louisiana, the Gulf Coast state is dealing with the devastation caused by another powerful hurricane, Ida. Data from the United States Geological Survey released over the weekend puts the Category 4 storm's strength in perspective, revealing it was powerful enough to force the Mississippi River to flow backward.

"The river reversal, as a whole, was very uncommon -- Category 4 storms are even more uncommon," said Scott Perrien, a supervising hydrologist with the USGS Lower Mississippi Gulf Water Science Center in Baton Rouge, Louisiana. Perrien called this the second occurrence in recent history the river has backed up due to storm surge. The other was Hurricane Katrina.

The latest climate report, released by the United Nations Intergovernmental Panel on Climate Change earlier this month, says human-generated carbon emissions are the likely reason were are seeing increases in uncommon, high intensity hurricanes like Ida.

The river reportedly reversed for about three hours on Sunday, when the violent hurricane first made landfall in Louisiana with high winds of 150 mph (241 kph). Perrien explained that the team recorded "data of up to a half a foot a second in the negative direction" after the water level rose roughly 7 feet (2.1 meters) during the storm. 

Perrien noted, however, that the measuring gauge that caught the river's flow reversal may not have detected deeper levels of water that could have remained drifting in the right direction.

Now weakened to a tropical storm, Ida has already led to one reported death and left the entire city of New Orleans without power.