Hurricane Helene has reshaped the Gulf Coast. The United States Geological Survey said erosion is to blame.
Kara Doran is a scientist at the USGS in St. Petersburg. She said sand dunes are essential in preventing beach erosion and are a crucial component in protecting communities from high storm surges.
“Areas with nice, high, wide sand dunes are protected from a lot of the effects of the storm,” Doran said. “Because as those water levels rise and the large waves come in they’re gonna impact the dune first and the dune can absorb a lot of that wave energy.”
They provide protection and allow for beach renourishment to occur at a faster rate. Doran said without human intervention, it would take Mother Nature years or even a decade to return beaches to their natural states.
“Communities don’t want to wait that long for that process to take place,” she said. “So working with human intervention and engineering can bring that sand back to the beach (and) can rebuild the dunes.”
Dunes are also the first line of defense in protecting infrastructure from high water levels.
When they are substantially eroded, inland structures are exposed to storm surge and waves. On barrier islands, the absence of dunes has the potential to increase storm surge, according to a USGS study.
Helene’s storm surge brought the highest water levels ever recorded in Clearwater and St. Pete, Doran said. It exposed flood water to many communities that had never seen it before.
Regardless, Doran said Helene is making some areas rethink how to manage its coastlines.
“I think in my time at the USGS, it’s definitely the most extreme erosion event that we have seen locally for sure,” Doran said.
In the future Doran said she hopes to see more engineering with nature-based solutions.
“Instead of building seawalls and putting rocks on the beach, there are more natural solutions such as building vegetated dunes,” she said.
While the total impacts of Helene have not been confirmed, the hurricane moved a large amount of sand from the beach.
“When a beach is overwashed, sand can be pushed and deposited inland, causing significant changes to coastal landscapes and blocking roadways. Overwash can reduce the height of protective sand dunes, alter beach profiles, and leave areas behind the dunes more vulnerable to future storms,” a press release from USGS said.
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