As residents of the Gulf Coast and parts of Central Florida dig out from two beatings by powerful hurricanes in two weeks, they may be puzzled by two very different storm surges.
The first strike by Hurricane Helene caught some a little off-guard as it made its way from the Caribbean into the Gulf of Mexico and trekked parallel to the coastline. As the sprawling storm passed the Tampa Bay region more than 100 miles from shore, its counterclockwise winds had plenty of time to propel a storm surge that battered and flooded the coast before Helene finally made landfall in the Big Bend.
Milton arrived nearly as fierce, with winds just 10 mph slower. But its wind field was smaller and its aim direct, blazing a path from the west side of the Gulf to the east side.
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“So the duration of time that that water is blowing onshore is less,” said Randy Parkinson, a geologist at Florida International University who studies the impacts from climate change on vulnerable coastal areas. “Whereas on the opposite side of Milton, the wind was actually blowing offshore,” draining Tampa Bay.
The one-two punch will likely spur more intense debate over the future of Florida’s Gulf Coast after a string of powerful storms. Especially since , particularly in the Gulf where water levels have risen 6 inches off the southwest coast since 2000, Parkinson said.
This week, outgoing Florida Senate President Kathleen Passidomo said lawmakers would likely make hurricanes the focus of the next legislative session, which begins in March 2025.
What makes a surge become so hazardous depends on a bag of ingredients, Parkinson said. In addition to the speed and direction of winds, surge is defined by tides, nearshore water depth, how the surge accesses the coast, what kind of coast it encounters, how it’s funneled ashore, how far it travels onshore and, importantly, what lies in its path.
In the coming months, the National Hurricane Center will issue , detailing the mechanics of each storm that include storm surge levels and wind speeds. Fatalities and damage assessments will also be included.
When surge began flooding St. Pete Beach, one of the hardest hit areas, the evening of Sept. 26, it was located more than 100 miles west of Tampa Bay, with sustained winds of 130 mph and traveling quickly at 23 mph. Homes quickly filled with water.
By comparison, tropical storms force winds from Milton began hitting the Tampa area about 11 a.m. Wednesday when the eye was located about 190 miles offshore. By the time it made landfall near Siesta key about 8:30 p.m., half the storm’s winds were blowing water offshore.
"I don't know how this ends, but it's a recipe for an extremely challenging coastal zone management. You've got the financial issues and all that, but people are dying."Randy Parkinson, geologist at Florida International University
What worries Parkinson is how coastal areas will rebuild.
“Going out to 2050, we're looking at another foot or two and that's just assuming that [sea level rise] is linear. But we know that is not true. We know that the rate of sea level rise is accelerating,” he said.
When homes are rebuilt in coastal areas, they can be elevated. But that’s not a long-term solution, he said.
“It's a recipe for disaster, not only with regards to the damage to property, the loss to life, the desire to rebuild, insurance, mortgage loans,” he said, continuing the list. “The ability to evacuate. I think that's the forgotten risk.”
Adaptive management, the strategy used by planners to pivot with changing hazards, is not keeping pace with conditions, he said.
“It's not progressing at the same rate as our confidence in our knowledge about the climate, about tropical cyclones, about the potential impacts,” he said. “It's slow because there's so many different fractions and perspectives on how to live, work and play in the coastal zone.”
But these storms, he said, show mitigation efforts like raising roads, building seawalls, elevating homes, building bigger stormwater systems or continually adding sand barrier islands has not kept pace.
“I don't know how this ends, but it's a recipe for an extremely challenging coastal zone management,” Parkinson said. “You've got the financial issues and all that, but people are dying.”
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