Rivers can fuel hurricanes, new USF study finds

The big picture: Hurricane Idalia surged from Category 1 to Category 4 in less than 24 hours as it neared Florida's Big Bend in August 2023, a phenomenon known as rapid intensification.

• Hurricanes Helene and Milton did the same. Each time, the abrupt spike made it harder for forecasters to assess the storms' impact.

Zoom in: Researchers studied a large plume of freshwater that stretched from the Mississippi River to the Florida Keys, and found that where it met saltwater, ideal conditions for rapid intensification were created.

• The freshwater from rivers along the Gulf Coast created a thick surface layer that did not mix with the cooler saltwater below, keeping the surface water warm and potentially fueling storms.

What they're saying: "Our study demonstrates the value of considering the influence of river plumes on storm intensification," said Chuanmin Hu, a professor of oceanography at USF and one of the study's authors.

• "If there's a persistent river plume in the right location at the right time, you might have the perfect conditions for a powerful storm."