Hurricane Ian is heading toward Florida and is expected to make landfall at Category 4 strength.

Hurricane Ian is barreling toward the Florida coast, with winds reaching upward of 155 mph after rapidly gaining strength in the past two days, reaching just short of Category 5 by Wednesday morning. The storm has already knocked out Cuba’s entire power grid after hitting the island Tuesday.

But wind and rain alone aren’t what’s making Ian such a serious threat. Florida’s population has been growing in recent years, with some of the largest increases in vulnerable coastal cities like Tampa, which is likely to receive a strong blow. Forecasters are getting better at predicting where hurricanes will go. However, they are still struggling to anticipate how intense they can become. All the while, hurricanes are capturing more people and property in their wakes as they become more damaging and as more people move to risky areas.

“Catastrophic storm surge inundation of 12 to 18 feet above ground level along with destructive waves are expected,” the National Hurricane Center warned on Wednesday. The highest-risk areas span from Englewood to Bonita Beach along Florida’s southwest coast.

Hurricane Ian is expected to bring storm surges as high as 18 feet.

A storm surge occurs when a hurricane’s winds raise water levels and sweep them inland, leading to flooding. This is often the deadliest part of a hurricane. Ian is also projected to drench parts of Florida, even further inland, with as much as 25 inches of rainfall. Floodwaters could linger for days.

These effects are getting worse because of climate change. Rising average temperatures are lifting sea levels and increasing the amount of rainfall from major rainfall events, adding up to more destructive storm surges. The increasing devastation from extreme weather events, many worsened by climate change, is helping fuel a rise in disasters with damages exceeding $1 billion.

But in Florida, as in much of the country, these costlier disasters also stem from the fact that more people are living and building in harm’s way.

Around 40 percent of the US population lives in a coastal county. Florida, however, has seen large increases in residents in these areas. From 2010 to 2020, Miami gained more than 660,000 residents, while Tampa-St. Petersburg grew by more than 365,000 people, according to the Florida Department of Transportation. The Tampa Bay metro region is home to more than 3 million people, with homes, offices, and roadways built right up to the water’s edge in some areas, including regions vulnerable to inundation. “The farther up the bay, the worse the hurricane storm surge potential,” Bob Weisberg, an oceanographer who studied flooding in Tampa Bay, told Vox’s Brian Resnick in 2019.

Between 2010 and 2020, urban coastal areas in Florida have seen large increases in population.

Florida’s sunny beaches are a powerful draw, but the state and local governments are also encouraging more people to move to the shores of the Sunshine State. With no state income tax, many local governments in Florida rely on property taxes, creating an incentive to develop more property.

“You’ve got these coastal cities who are making a gamble by encouraging development even though it might not be environmentally sustainable or a good idea for people to live at greater risk,” said Jason von Meding, an associate professor who studies disasters and society at the Rinker School of Construction Management at the University of Florida.

As more people move in, the homes, businesses, and infrastructure they need grow as well. So when a storm tears through a region, it leaves behind a much higher damage bill.

However, von Meding said his main concern isn’t that there are “too many” people in Florida, but rather where they choose to build and how the burden of disasters is spread out. For instance, the dollar value of damages doesn’t always reflect who is most at risk and who suffers the most in the wake of a hurricane. Expensive, insured coastal vacation homes may register as higher losses than the sole residences of low-income families.

Thankfully, fewer people are dying from extreme weather events like hurricanes. Better building codes, disaster planning, and forecasting have helped people get out of the path of danger. Hurricane modelers can now project the path of a storm 72 hours in advance with a level of detail that decades ago was only possible 24 hours in advance, buying crucial time.

But anticipating the intensity of a hurricane remains a challenge. Some studies have shown that more Atlantic hurricanes are undergoing rapid intensification, defined as a wind speed increase of 35 mph or more over 24 hours. As average temperatures rise, hurricanes are likely to spool up faster, making it harder for residents to evacuate in time.

A storm doesn’t have to reach hurricane strength before it becomes dangerous, either. Miami is already seeing flooding with King Tides and severe rainfall on a regular basis, worsened by the fact that parts of the city are sinking. More than 10 inches of rain fell on Miami during a storm earlier this summer that flooded streets and caused a sewage plant to overflow.

Miami was inundated with rainfall this summer.

Cities like Tampa are now grappling with even more devastating storms in the future. In one scenario, planners are considering a direct hit from a Category 5 hurricane with 160 mph winds driving a 26-foot storm surge.

A storm’s destruction doesn’t end after the floodwaters recede, however. Many inequities can continue to propagate. People without insurance or the means to rebuild may have to permanently relocate or face lasting financial hardships. “Recovery processes prefer people who already have resources,” von Meding said. “We often see an exacerbation of inequality after a disaster.”

Puerto Rico is a case in point. More than 300,000 customers are still in the dark as of Wednesday morning after Hurricane Fiona swept over the island last week. Without power, many residents are struggling to get clean drinking water and run critical medical devices. So the full damage of a storm isn’t just a function of wind and water, but how people prepare and how quickly they recover.

Ian is poised to begin pummeling Florida on Wednesday and make its way up the Gulf Coast. Utilities are now preparing for outages and lining up crews to restore power in Ian’s wake.

Update, September 28, 11:40 am: This story, originally published September 26, has been updated with Hurricane Ian’s current forecasted path and strength, and damage reported from it to date.

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