Severe Coastal Flooding in Florida Is Getting Worse, New Study Finds

Anyone who’s ever lived on South Beach knows the moment. Thunder booms, rain pounds down in solid sheets of water, and then it happens: The streets suddenly turn into rivers, sending cars and pedestrians bobbing in the massive buildup of precipitation.

Floods are part of the contract that comes with living in low-lying, tropical-weather-prone South Florida. But that contract is coming due much more often — and at a higher cost.

That’s the finding published in a new paper by a team of scientists led by Dr. Thomas Wahl, a post-doctoral researcher in marine science at the University of South Florida. The group studied a century’s worth of data and discovered that flood severity on the East Coast is growing steadily worse.

“We found this tendency is most pronounced around the Gulf Coast and Florida’s coastline,” Wahl tells New Times.

Wahl, a native of Germany, came to Florida on a fellowship to study flood risks. He became interested in studying two factors behind big floods: storm surges — the wall of water pushed up by large storm systems — and massive amounts of precipitation. How often did the two combine into colossal “compound” floods?

He and his co-authors began collecting historic hurricane track, rainfall, and tide readings. They eventually reached two conclusions — published earlier this month in Nature Climate Change — both of which should worry anyone in Miami-Dade County.

The findings clearly show that there’s a link between heavy rain and storm-surge flooding and that the number of compound floods in urban U.S. coastal cities is on the rise.

What’s behind the increase? Climate change and sea-level rise are likely culprits, but that answer is beyond the scope of Wahl’s work.

“We can’t really tell yet if it’s climate change or part of a natural cycle,” he says. “But we know that sea-level rise will continue and certainly have an effect on flooding.”

Wahl says he hopes urban planners in places like Miami Beach — where a $300 million project is underway to install 60 anti-flood pumps — can use his work to more effectively plan.

“This is just a starting point,” he says. “The results show this is a complex topic that needs more detailed research for improved flood maps.”
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Tim Elfrink is a former investigative reporter and managing editor for Miami New Times. He has won the George Polk Award and was a finalist for the Goldsmith Prize for Investigative Reporting.
Contact: Tim Elfrink