Hurricanes are intensifying more rapidly – and the most vulnerable communities are hit hardest

Chelle Walton remembers how the water rushed into her home, the night Hurricane Ian made landfall. The 68-year-old found herself chin-deep in water, scrambling to grab essentials like her husband’s medication. “Strangely enough, things float in saltwater,” Walton said.

Walton and her husband Rob had decided to shelter in place, despite repeated evacuation notices.

“You make all of your decisions based on past storms,” said Walton. “It turned out to be a bad decision.”

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Walton has lived through four major hurricanes since she moved to Sanibel, a barrier island off the Florida coast in 1981. If she could go back, she says she would have left the day before landfall. “We will never stay again,” Walton said.

Hurricane Ian, a devastating category 5 storm that led to 149 deaths across the state of Florida, was one of the most powerful hurricanes to ever strike the US. It demolished homes and businesses and left more than 2 million without power. Part of its devastation stemmed from how quickly it progressed; as the storm approached the US, Ian underwent a dramatic and difficult-to-predict escalation in a short amount of time, a phenomenon known as rapid intensification. With climate crisis warming the oceans at a record pace, scientists say these types of storms are occurring more frequently. And unless coastal communities like Sanibel invest in robust disaster preparedness, residents may continue to find themselves blindsided by these extreme weather events.

“If you look back in time, historically, storms intensified at a slower rate than they do now,” said Phil Klotzbach, a researcher at Colorado State University who specializes in hurricane forecasting. “If you’re expecting a category 1 hurricane, and you get a category 5, that has a very different set of impacts in terms of the winds but also the storm surge,” Klotzbach said.

Predicting when rapid intensification will strike – and effectively communicating the dangers of such an event to community members – poses challenges for evacuation and emergency management systems.

“It’s one of the most important challenges facing our field right now,” said Alex DesRosiers, a researcher at Colorado State University specializing in intensity change. Some recent storms have seen wind speeds increase by 60mph (96.6km/h) in a day. “That’s the difference between a category 2 and a category 5,” DesRosiers said. One such example is Hurricane Michael. In 2018, this devastating storm jumped from a category 2 to category 5 the day before making landfall in Florida.

From 1950 to 2023, meteorologists identified a total of 482 hurricanes in the Atlantic Ocean. These are storms with maximum winds of 74mph (119km/h) or greater. Of those, roughly 60% of them underwent rapid intensification – meaning their wind speeds increased by 35mph(56.3km/h) or more in a 24-hour period. Research shows that since 1970s, the number of storms escalating into category 4 or 5 hurricanes has roughly doubled in the North Atlantic.

The fierce wind is what Iris Bergeron remembers most about Hurricane Ida, another storm that rapidly intensified in 2021. For nearly a month after landfall, she worked in St James Parish, one of the areas of Louisiana hardest hit by the storm, helping displaced people move into shelters. When Bergeron returned home in nearby St John the Baptist Parish, her front door refused to open, swollen by water damage.

“I just wept like a baby,” Bergeron said. After several tries, the door gave in and she made her way into a home that stank of spoiled seafood from her freezer. As she felt the softness of damp walls, stumbling on fallen wires and drywall, she looked up to see a hole in her ceiling. “I knew the insurance wasn’t going to be enough, [and] my house was not going to be the same.”

The communities likely to be hardest hit by rapid intensification may also be historically disadvantaged by decades of racist housing policy. In the 1930s, the US government created a series of maps which showed where Black people, immigrants, and other minority groups lived, deeming these “redlined” areas as risky investments. These discriminatory practices ensured that both public and private entities like banks and insurance companies systematically denied housing or financing of mortgages to Black families and other households of color.

“What that meant is that those families disproportionately ended up in substandard housing and high flood-risk areas,” said Hannah Perls, a senior staff attorney with the Harvard environmental and energy law program.

While outlawed with the passage of the Fair Housing Act of 1968, its legacy persists and is felt in communities of color to this day.

“When a disaster comes along, either their house is not built to stand up to that disaster or they’re in areas that are getting heavier winds, flooding and impacts,” Perls said. The disproportionate impact of extreme weather on these vulnerable communities also continues after the storm, hindering recovery efforts. “There’s a legacy of discrimination, still, in the way that homes are assessed in terms of their value or people’s ability to access insurance.”

Bergeron’s home insurance company was one of nearly two dozen that have either gone bankrupt or abandoned their operations in Louisiana post-Ida.

The complexity of forecasting when storms turn volatile adds an additional challenge to communication efforts. The National Hurricane Center (NHC) responsible for tracking the intensity of storms in the US, issues hurricane and storm surge warnings, which can inform states and municipalities when to trigger evacuation notices.

“We’ve gotten substantially better at predicting these rapid intensifiers,” said the NHC deputy director Jamie Rhome. “The challenge we now face is that so many people infer their risk of a hurricane based off what it is now, not what it will be in the future.”

While advancements in weather forecasting, thanks to satellites and drones, allow scientists to better observe this phenomenon, it’s still difficult to measure conditions inside the hurricane, which contribute to its structure as a whole.

“We know from the satellite what kind of environment makes a hurricane go,” said DesRosiers. “But what we don’t know is what’s under the hood, underneath those clouds – what are the internal makings of a hurricane that will blow up very quickly in that environment?”

In the past three years, Louisiana was hit by two rapidly intensified storms back to back, Hurricane Laura and Hurricane Ida, within a year of each other.

“We’ve lived through a lot of hurricanes,” said Lori Cooke, a resident of Sulfur, Louisiana, who remained in her home until the day before Hurricane Laura made landfall in 2020. Persuaded by her son, she evacuated two hours north to his apartment in Baton Rouge with her pets and what she believes was the last generator her local Home Depot sold that day.

“By the time you know, it’s bad, so many people now are trying to leave that you’ve just got gridlocked, and it’s hard to find a place to stay,” Cooke said.

Getting people to believe and understand that a storm is going to intensify remains a major challenge when it comes to warning residents of impending risk. Experts say that much too often, people anchor their expectations and decisions to evacuate on the current intensity or the current satellite depiction versus the predicted.

“Because these storms go from a category 1 to a major hurricane very quickly, it leaves a lot of people unprepared,” said Jennifer Collins who researches hurricanes and human behavior relating to evacuation at the University of South Florida. “If we say all along that it’s going to be a major hurricane, then people can prepare for it. But if people see it only a day before as a tropical storm then they feel complacently that they’ve got plenty of time to prepare for it, but that’s not the case anymore.”

As ocean waters are getting warmer, these storms are not only getting stronger but also intensifying from a weak hurricane to a strong hurricane in a shorter window of time.

“Increased greenhouse gas emissions have warmed the planet but they’ve also warmed our oceans, and those warm ocean waters fuel the storms,” said Andra Garner, climate scientist at Rowan University, who analyzed maximum changes in wind speed for Atlantic tropical storms from 1971 to 2020. “Across the board, we are seeing storms strengthening more quickly,” Garner said.

One measure that communities could do to better prepare for high impact storms is through protective evacuations. “The fact that we have these storms that can rapidly intensify, would say that we should adopt the precautionary principle to ensure that folks aren’t trapped in these really catastrophic storms,” said Perls.

The personalization of risk is also key in helping people to understand that they themselves will be in danger from a particular storm.

“The ability to help people to envision themselves in that disaster, versus seeing it as ‘something that’s going to be over there, or be somebody else’s problem’,” said Rhome.

Emergency planning that involves the disabled, people without the means of evacuation, and the elderly members of the community is crucial for preparing for rapidly intensified storms ahead of time.

“It’s really important to ensure that municipalities and states are engaging in those comprehensive planning processes, and making sure they’re accounting for and hearing from the most vulnerable folks,” said Perls.