And that's no surprise: Florida sticks out from the North American continent like a hitchhiker's thumb. Hurricanes spiraling across the Atlantic are driven to it by winds and currents. The narrowness of the state only increases its vulnerability: it's the only state that is vulnerable on both sides, east and west. A big storm like Irma can swallow the whole southern part of the state.
The average elevation of Miami Beach -- a thin barrier island across Biscayne Bay from the city of Miami -- is even less. The highest point in South Florida is Orlando, which towers above the state at nearly 100 feet.
The Florida Keys are mostly low-lying mangrove islands; one of the highest points is the famous Key West cemetery, where 60,000 people are buried, including Civil War heroes and slaves, which is about 8 feet above sea level. In Tampa Bay, it's not only the city's low elevation, but also the shape and depth
of the bay itself, which tends to amplify storm surges.
The very rock
South Florida is built out of is a problem, too. "Imagine Swiss cheese, and you'll have a pretty good idea what the rock under south Florida looks like," a senior engineer at the US Army Corps of Engineers once told me.
This means that water moves everywhere through the ground, bubbling up in unexpected places. It also means that it is very difficult to build sea walls and other barriers to protect against storm surges and rising seas.
For most of Florida's history, none of this really mattered, because nothing lived there but mosquitoes, alligators and crocodiles (South Florida is the only place in the world where the two species coexist.) In the late 19th century, one Seminole War veteran called it
"by far the poorest and most miserable region I ever beheld."
But in the early 20th century, get-rich-quick artists and wanna-be real estate tycoons dug canals to drain the swamps, built islands in Biscayne Bay, and created a kind of paradise. Today, about six million people
live on the east coast of South Florida, from Miami-Dade county up through Palm Beach. Pinellas County, on the west coast of Florida, is the densest-populated county in Florida, and Tampa Bay is the fastest-growing
metro area in the state (and the fourth-fastest in the nation).
And when it comes to hurricanes, more people equals more risk.
More people also equals more infrastructure: the homes, roads, bridges, electrical lines, sewer systems and everything else that allows us to live so comfortably in a swamp. And the bigger the population, the more stuff there is to be damaged, blown over or destroyed.
In south Florida, the real problem is that much of this infrastructure is built right on the water. After all, the whole reason people live in Florida (or just have a romantic attachment to it, as I do) is because they love living near the water. And in South Florida, despite the obvious risks, construction along the coasts is booming. Just look at all the construction cranes on the Miami skyline.
Even more telling (and disturbing) is the growth in southern Miami-Dade county, a low-lying and extremely vulnerable area that got wiped out by Hurricane Andrew in 1992. In 1990, South Miami-Dade's population was just over 300,000; today, it's nearly 528,000. Since 1990, the region has more than doubled
the number of housing units, from 75,000 to more than 190,000.
Similarly, rapid growth along 700 miles of waterfront in Tampa Bay explains why a 2015 insurance industry study ranked the city the most vulnerable
in the US for storm surge damages. Instead of retreating out of harm's way, Floridians have doubled down.
There are a lot of reasons why South Florida has continued booming, despite the obvious risks: affordable real estate, nice weather, proximity to water, low taxes (Florida has no state taxes). And there are lots of reasons why Florida officials worked hard to accelerate the boom, even in risky coastal areas; but the most basic truth is that real estate and tourism are the twin engines of South Florida's economy.
Nobody wants to put a damper on either one of them. In addition, cities and counties are dependent on property taxes for a large part of their revenues, which means the more they build, the more money they have (in theory) for cops and schoolteachers.
To put it bluntly, the Florida economy is a kind of real estate version of a perpetual motion machine: To keep government funded, they have to keep building and building. And if a hurricane comes along and blows everything over every 30 years, the thinking goes, so what? The feds will help us out and we will rebuild Florida bigger and better than before.
That was a workable thesis in, say, 1950. But thanks to climate change, our world is changing fast now. That 30-year gap may be getting narrower, and the storms more devastating. Even the best scientists can't say exactly what kind of climate-driven chaos is in store for us in the near future -- but one thing is certain: South Florida is only going to become more vulnerable in the coming years, not less.
The risk is not just from bigger, more intense hurricanes driven by a rapidly warming ocean. For Florida, by far the biggest threat is rapid sea level rise. Andrea Dutton, a researcher at the University of Florida, recently found that, due to El Nino and other factors, between 2011 and 2015, the seas rose six times faster
in South Florida than the long-term global average.
In the longer term, the National Oceanic and Atmospheric Administration (NOAA) recently estimated
that the seas could rise as much as 8 feet by 2100. And it won't stop there.
Eight feet of sea level rise would, of course, be a catastrophe for a low-lying place like South Florida. To get an idea of what it would be like, consider the storm surge we'll be seeing with Irma, which is projected to hit 8 feet or more in some places -- and then imagine the water never leaves.
But even more moderate sea level rises will be a problem: it means higher tides, more nuisance flooding, more washed-out roads, more saltwater intrusion into drinking water aquifers, more corroded electrical lines, more septic tanks leaking bacteria-laden waters into the streets, and, of course, higher, more damaging storm surges when hurricanes hit.
Does this mean South Florida is the next Atlantis? That depends in large part on how quickly we get our act together to cut carbon pollution. Smart building and city planning can also reduce the risks. But, ultimately, as the destructive path of Hurricane Irma has demonstrated, Mother Nature is boss. Maybe it's time we pay attention to her.