The Mississippi River rose by nearly seven feet due to the storm surge from Hurricane Ida. The storm surge and the 150 mph winds were enough to stop the flow of the river and actually cause it to move in the opposite direction.
“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, Louisiana, told CNN.
Perrien said that Ida is causing flooding up and down the river and warned that it will only worsen as the storm moves inland.
“The river is feeling the effects of the storm over a large area,” Perrien said, “all the way up to Baton Rouge, the river has risen 1.5 feet in the past 12 hours as the surge pushes up the river. And the water level will likely rise more in the coming hours here in Baton Rouge.”
The storm surge was so powerful that two ferries broke from their moorings and were floating uncontrolled down the river.
Perrien said that it is "extremely uncommon" for the river to reverse directions but noted that it happened during Hurricane Katrina.
"I remember, offhand, that there was some flow reversal of the Mississippi River during Hurricane Katrina, but it is extremely uncommon," Perrien said.
Ida made landfall as a powerful Category 4 storm on Sunday (August 29), exactly 16 years after Katrina slammed into the Gulf Coast.