The third hurricane in 13 months is churning the Gulf of Mexico as it crashes into Florida’s northwest coast, threatening a region still recovering from recent extreme weather with historic storm surges and dangerous winds stretching hundreds of miles.
But Hurricane Helene, which followed last year’s Hurricane Idalia and last month’s Hurricane Debby, was no ordinary storm, even by Florida standards. Like other high-profile climate storms over the past few years, this storm is expected to undergo what meteorologists call “rapid intensification” and gain strength at an alarming rate as it passes through unusually warm Gulf waters. As a result, it is poised to make landfall as a Category 3 or 4 storm just a few days after it first formed in the Caribbean. It could also grow into one of the most widespread storms on record, bringing life-threatening winds and rain all the way into inland Tennessee.
Hope Webb, a real estate agent who lives in a coastal area of the sparsely populated Big Bend region, said Thursday that she was hunkering down and hoping for the best as the storm was expected to make landfall Thursday evening.
“I am a lifelong resident of this area,” she told Grist. “I have been through many storms. I believe that God has his arms around us. “But this storm is definitely testing our strength.”
Three factors conspired to make Helene a particularly powerful storm. Like any hurricane, its fuel is warm ocean water, which evaporates and injects energy into the atmosphere. As Helene moved through the Caribbean, it at least ingested the unusually warm ocean temperatures it generated. 300 times higher risk due to climate changeAccording to experts. As we continued our march north toward the Gulf Coast, we found unusual strength in both. warm and deep — A very large pool of high-octane fuel.
Additionally, wind shear (a term for the tendency of winds to move in different directions and speeds at different altitudes) in the area is low. Atmospheric turbulence generally puts a lower ceiling on the strength of a hurricane. Finally, high humidity was another factor in Helene’s favor.
“We had almost perfect conditions,” said Karthik Balaguru, a climate scientist who studies hurricanes at the Pacific Northwest National Laboratory.
The combination of warm deep-water fuel, high humidity, and low wind shear put Hurricane Helen on the cusp of rapid intensification, which technically means sustained wind speeds increased by more than 35 miles per hour within 24 hours. Scientists made a dramatic discovery. Rapid increase in number of reinforcements In recent decades it has moved closer to the coast.
“A clear sign of climate change is the increasing rate of intense hurricanes,” Balaguru said. “Storms tend to intensify faster and faster, especially near the coast.”
This makes hurricanes more dangerous than ever. For example, a coastal city may be preparing for an approaching Category 1 hurricane, but it may suddenly turn into a Category 3 hurricane. The more powerful a hurricane is beyond the coast, the better it can withstand dissipation as it moves over land. And you lose your fuel source. And as the atmosphere warms, it can hold more moisture, which can lead to more rainfall from hurricanes.
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For communities along the coast, it’s not just the winds and rainfall that make storms like Helene so dangerous, but also the storm surge. Hurricane winds push water towards the coast. This is a dangerous outcome for areas like the Gulf Coast, which are already experiencing sea level rise.
The terrain on Florida’s west coast makes the situation even worse. In some beach areas the sea depth drops dramatically right off the coast, but here Depth gradually increases As we move away from the coast. If the water near the coast is deeper, the storm surge may be partially absorbed by this depth, weakening its impact on land. But because of the shallow waters off Florida, the water has nowhere to go but straight into coastal communities.
The eye of Helen is expected to make landfall around Tallahassee Thursday night, but the hurricane’s strongest winds tend to come from the northeastern part of the storm. As for St. Helene, those winds are poised to hit Florida’s less developed Big Bend region, which was worst affected by Idalia last year. that part of the country located in extremely low-lying areasStorm surge can therefore rush inland unimpeded by geographic features that are normally mitigating factors. In towns like Steinhatchee, just south of where Hope Webb is riding out the storm at her beachfront home, expected surges could reach 20 feet. In a release Wednesday night, the National Weather Service office in Tallahassee called the conditions “catastrophic” and “potentially unsurvivable.”
Farther south, the populous Tampa Bay region is also poised to see record surges after decades of near misses. “The shape of the coastline in that area makes it easier for storm surge to build up,” said Samantha Nebylitsa, who studies hurricanes at the University of Miami. “It kind of flows into Tampa Bay, so there’s nowhere for the water to go other than that area.” Many estimates suggest that Hurricane Helen is set to: Breaking surge records More than 2 feet.
Early Thursday morning, the storm was still hours away from passing through St. Petersburg, but the winds were already starting to pick up and the sky was darkening. Several gas stations in the city’s downtown ran out of fuel as residents filled their tanks, and most people living in low-lying areas fortified their homes against flooding with sandbags, tarps and door sealant. Flashing signs reading “HIGH WATER EXPECTED” warned drivers to stay away from the shoreline. Counties along the Gulf Coast, including the cities of Tampa and St. Petersburg, have issued mandatory evacuations for residents in storm surge areas and those living in mobile and manufactured homes. The streets of the beach city of Clearwater were already experiencing localized flooding.
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Hurricane Helen is a huge storm. Those winds have a range of more than 400 miles. So the rain will clear from the Georgia coastline and the Carolinas into Missouri and Arkansas. From Thursday morning, All counties in South Carolina, Georgia, and Tennessee We were getting some kind of flood or wind warning. Forecasters are warning of hazardous winds that could cause flash flooding in mountains east of Knoxville and Chattanooga, Tennessee, and widespread power outages across Georgia, especially as the storm stalls.
Like a car accelerating to higher speeds, Hurricane Helen could travel farther inland without losing momentum, considering how much it picked up speed as it passed through the very hot Gulf waters.
“You will essentially be rushing yourself into this state,” Nebylitsa said. “And at that speed, it’s going to take a lot more time for it to slow down.”
Whether coastal or inland, all of these areas have significant development that makes them particularly vulnerable to flooding. The Florida coast has thousands of homes in low-lying coastal areas that could easily fall prey to storm surge, and states like Georgia and North Carolina have built thousands of homes near rivers and streams that are likely to flood as Helen passes through. As intense hurricanes like Helene occur more frequently, these vulnerabilities are being exposed.
“We are entering a new normal that we will experience under climate change,” said Michelle Meyer, director of the Center for Risk Reduction and Recovery at Texas A&M University. “But secondly, it’s been a longstanding fact that we continue to build in some really dangerous places and in some pretty dangerous ways. So if we continue to add homes in areas that flood regularly, or if we add homes on the coast without greater mitigation measures, we’re going to see increasingly higher risks.”
Ayurella Horn-Muller contributed reporting to this article.
