Hurricane Ida was so powerful it actually reversed the flow of the Mississippi River.
A US Geological Survey gauge detected the flow reversal in the Mississippi River near New Orleans on Sunday after the hurricane blasted ashore as a Category 4 storm.
The strong storm surge saw the flow reversed in a portion of the river for about four hours.
Scott Perrien, a USGS hydrologist, told CNN the flow reversal was “extremely uncommon.”
He said the river level rose seven feet Sunday due to the storm surge.
“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,” he said.
Perrien noted there was also some flow reversal in the river during Hurricane Katrina in 2005.
Hurricane Ida made landfall Sunday packing winds of up to 150 mph – exactly 16 years after Katrina ravaged Louisiana and Mississippi.
Louisiana authorities reported the first death from Hurricane Ida Sunday night after a 60-year-old man was was fatally struck by a fallen tree.
Ida — one of the most powerful storms ever to hit the US — knocked out power to all of New Orleans and blew roofs off buildings as it rushed ashore.
The storm crawled inland and dropped to a Category 1 hours later as it passed within 30 miles of New Orleans.
More than 1 million customers were without power in two southern states impacted by Ida — more than 930,000 in Louisiana and 28,000 in Mississippi, according to PowerOutage.US, which tracks outages nationwide.