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Gulf currents slowed in 2022, fueling Hurricane Ian's wrath in Florida

Hurricane Ian developed from a Category 3 to 5 before it hit Florida in 2022.
NASA Earth Observatory
/
Lauren Dauphin
Hurricane Ian developed from a Category 3 to 5 before it hit Florida in 2022.

A new study by University of South Florida researchers shows a slowdown in the loop current that funnels warm water into the Atlantic Ocean helped intensify Hurricane Ian in 2022.

The current failed to reach the continental shelf off Florida's Gulf coast. It couldn't reach the Florida Straits, where it creates the Gulf Stream that flows northward in the Atlantic. That meant warmer water staying in the Gulf fueled the hurricane, which briefly reached Category 5 before plowing into Lee County at Category 4.


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Yonggang Liu , lead author of the study and director of the Ocean Circulation Lab at USF's College of Marine Science, says just before Ian made landfall, the loop current seemed to be stuck in neutral.

That meant colder, deeper water didn't flow in the shallow continental shelf, called the West Florida Shelf. So Gulf waters remained unusually warm, feeding the intensity of the hurricane.

Yonggang Liu is director of the Ocean Circulation Lab at USF's College of Marine Science.
Cliff McBride / University of South Florida
/
University of South Florida
Yonggang Liu is director of the Ocean Circulation Lab at USF's College of Marine Science.

Liu says the loop current never made it to a critical point near the Dry Tortugas. That's where it can flush warm waters from the West Florida Shelf and replace it with cold water from deeper regions of the Gulf.

"Typically, there is a mixing of the water column where warmer surface waters interact with the underlying, often cooler subsurface water," said Liu. "But in this case, the shelf water was not able to cool down because the loop current did not initiate any upwelling."

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But he said it's difficult to predict the behavior of the current.

"The loop current behavior is very chaotic, not predictable at this time," Liu said. "To my knowledge, nobody can predict. It's not that easy."

The path of Hurricane Ian as it increased in intensity along the coast of Florida. Buoys and moorings deployed by the Ocean Circulation Lab picked up valuable water temperature data.
USF College of Marine Science /
The path of Hurricane Ian as it increased in intensity along the coast of Florida. Buoys and moorings deployed by the Ocean Circulation Lab picked up valuable water temperature data.

He says more ocean temperature monitors need to be built offshore to be better able to predict the strength of hurricanes.

"This needs to be expanded. Right now, we only implement on two moorings," he said of the sensors. "This needs to be expanded to more locations, and not only to our shore. We need to expand it to other coastal oceans."

The temperature of the subsurface layer of water is important for forecasters to monitor, according to Liu, as sea surface temperatures only give a glimpse into the heat available for hurricanes.

Prior to Hurricane Ian, surface waters were only 1 to 2 degrees Celsius warmer than average, while the subsurface waters were 2 to 3 degrees warmer.

"By not including the subsurface water temperature in models and forecasting, we are not getting the entire picture of the water column and the potential energy for hurricanes," Liu said.

Copyright 2025 WUSF 89.7

Steve Newborn is WUSF's assistant news director as well as a reporter and producer at WUSF covering environmental issues and politics in the Tampa Bay area.