When the storm—let’s call it “Atlas”—reaches the Gulf of Mexico, it might be only a tropical storm, with top wind speeds of 73 mph. But the warm waters of the Gulf will quickly fire it into a major threat, just as they did with Charley, which over a matter of hours in 2004 morphed from a low-level hurricane into a Category 4 with wind gusts of 145 mph. Atlas will be even deadlier, with a central pressure of 830 mb—Andrew’s was 922 mb—and sustained winds of 233 mph as it travels parallel to Florida’s west coast, then aims its fury straight at Sarasota. 

The keys will feel the effects first. Hours before the storm makes landfall, bridges to inland safety will be closed as the water rises, swiftly and silently inundating approaches and then the causeways themselves. Then the winds will rise, building into a screaming maelstrom, followed by a 20 to 25-foot storm surge of catastrophic destruction. Every barrier island, from Anna Maria to Manasota Key, will be submerged, with waves breaking above the roofs and treetops.

As it comes ashore, Atlas will carve a 22-mile-wide path of destruction—matching the width of the storm’s enormous eye—that will mow down trees and shatter buildings built to current hurricane codes. Tornadoes will spin away from the eye and race across the landscape, splintering everything in their path. Miles away from the eyewall, condominium windows will blow out and debris will rain from penthouses into the parking lots below. Wall-mounted TVs will be ripped from anchor braces. Coffee tables, designer couches and fine art—all blown away. The higher the dwelling, the stronger the winds.

Sarasota Bay will fill and overflow. Winds will strip the leaves and plants from Selby Gardens. Van Wezel will reflect purple in waters at least 15 feet deep. Water will cover more than half of the 26-foot-tall Unconditional Surrender statue at Bayfront Park—or smash it off its moorings.

The roads on the keys will break up and be swept away. The sea will rush over the land, depositing six feet of wet sand where roads once were, sand that will be blown dry as Atlas moves on.

Waterfront homes will fall into the Gulf and float down the bay; houses mounted on stilts to avoid flooding will be swept off their pilings. Small cottage-like homes, like those in Pinecraft, will be beaten to splinters.

No trailer park will survive.

As seawater rushes across the land, downtown Sarasota, higher than much of the county, will be spared the worst of the surge, with flooding measured in blocks. But a few miles south, water will submerge Bee Ridge Road at its intersection with U.S. 41 and creep east. South from there, large areas of the highway will lie under water. Flooding will be extensive and evacuations necessary in Laurel, Osprey, Nokomis, Englewood and Venice. Creeks and rivers will overflow as Atlas’ storm surge pours into bays and inland waterways. Interstate 75 will flood south of Clark Road and be impassable for the remainder of its route to Charlotte County.

Emergency services will be challenged. Low-lying Manatee Memorial Hospital will flood. And while Sarasota Memorial is on higher ground and might remain operative, its ground-level emergency entrances will be underwater. Ambulances won’t be able to get to them.

Some schools, government buildings and fire stations will be destroyed. Free-range cattle east of I-75 will be blown away. Cows will fly, just like in the movie Twister.

Many people will heed forecasters’ warnings and flee the county. Some will find themselves caught in massive traffic jams in blinding rain and winds that toss cars like confetti. But many others will choose to ride out the storm in their homes—and many of them—perhaps thousands—will die. The survivors will find themselves in an unrecognizable landscape of debris and destruction, living without power and basic services for weeks or even months.

That imaginary scenario sounds like a movie, a Florida disaster flick cooked up by an apocalyptic-minded Hollywood screenwriter. But if a pair of researchers is right, Atlas is far from a doomsday fantasy.

Last year, Kerry Emanuel, an atmospheric scientist and leading expert on climate change and hurricanes at the Massachusetts Institute of Technology, and Ning Lin, who teaches civil and environmental engineering at Princeton University, published a study on the possible effects of monster storms they called “Grey Swans.” Similar to Black Swans—author Nassim Nicholas Taleb’s term for unprecedented and unpredictable happenings—Grey Swan events would be without precedent and yet may be predicted by an analysis of past hurricanes, climate data and the impact of global warming.

From their data, Emanuel and Lin constructed computer models that whipped up a fury of virtual hurricanes, including a Frankenstorm that fed on ever-warmer waters and temperatures, exploding into a hurricane like none the world has ever seen, with winds topping 225 miles an hour and storm surges 35 feet and higher. (Hurricane Katrina’s record-breaking storm surge was 28 feet.) Then they estimated the effects of such a storm on three areas of the world they judged extremely vulnerable to them—the Australian city of Cairns, Dubai and Tampa Bay, about 50 miles north of downtown Sarasota. 

“We chose Tampa Bay as a place highly vulnerable to tropical cyclones and especially large storm surges,” Emanuel explained to us. Storm surges are the most destructive and deadliest aspect of hurricanes. And they’re bigger when the winds blow across shallow waters. With a continental shelf that extends 90 miles offshore, Tampa Bay is surrounded by an enormous expanse of shallow water. Those waters and the large numbers of coastal residents living at low elevations led the research group Climate Central in 2012 to name Tampa Bay the No. 1 most vulnerable U.S. city to hurricanes.

There’s another reason Emanuel and Lin chose Tampa Bay. Its residents, lulled into complacency after decades without a major hurricane, are unprepared. “A major hurricane near Tampa, while it would not be a surprise to meteorologists, would be somewhat unexpected among residents,” says Emanuel.

Grey Swans, many climate experts agree, are not super-heated figments of scientific imagination. They are, theoretically at least, entirely possible, given what we know about past hurricanes and the effects of climate change on storm formation. But although Grey Swans will be increasingly likely, scientists can’t predict today exactly where one will hit in the future. Just as the odds of any one person being hit by lightning are tiny, so are the odds of a Grey Swan hitting any one city. Right now, the probability of a Grey Swan with a storm surge of 46 feet making landfall at Tampa Bay is tiny: less than 1 in 10,000 years, according to the researchers’ calculations. But they warn that as the planet continues to heat up, by the end of the century such an event in our region will be 14 times more likely.

A hurricane is a heat engine. It sucks warmth from the ocean surface and tosses it high into the cooler upper atmosphere. The more heat the ocean provides, the faster the hurricane rotates around an eye. The faster it rotates, the stronger its winds become. The atmospheric pressure drops, and the hurricane pushes masses of rising sea water ahead of its eyewall. Global warming is a storm aphrodisiac. While other life may die as temperatures rise around the world, hurricanes will thrive.

So far, scientific models disagree about whether global warming will increase the frequency of hurricanes, but most agree that the storms that do form will be stronger. (One prominent meteorologist, however, Christopher Landsea of the National Hurricane Center, has said he believes they’ll get only slightly stronger over the next few decades.) According to Jeff Masters, director of meteorology for the website Weather Underground, we are already seeing more Category 4 and 5 hurricanes. As to a Grey Swan with winds of 225 mph? Masters points out that we’ve already had a hurricane close to that, citing Hurricane Patricia, which had winds of 215 mph—the strongest ever measured in the Western Hemisphere—before it hit the coast of Mexico in October of last year. 

Some experts believe hurricanes will increase in size as well as power. Bigger storms will build bigger storm surges. Rising sea levels will also fuel higher surges. In a recent blog posting, Masters cited a study by Tufts University that predicted that a 2.25-foot rise in sea levels—and some scientists are now predicting increases much higher over the coming decades—would inundate the homes of 152,000 people in Pinellas County.

And although the researchers chose to aim their storm at Tampa Bay, there’s no reason to think a monster storm couldn’t someday strike here, Masters told us.

“A Grey Swan storm with 200 mph-plus winds could just as easily hit Sarasota as Tampa,” he says. “The storm surge would cause catastrophic damage, and a swath of winds 20 miles wide at EF4-EF5 tornado intensities would wipe out thousands of houses. Steel-reinforced concrete buildings [in the storm-surge zone] would survive the storm but suffer blown-out windows and heavy water damage on their lower floors. The death toll would be in the hundreds, and in the thousands if evacuation orders are not heeded.”

The only storm in recorded history that came close to a Grey Swan at landfall was a hurricane that hit the Lesser Antilles in 1780. It was so intense, “It peeled the bark off trees—something only EF5 tornadoes with winds of excess of 200 mph have been known to do,” wrote Masters in a recent posting. That storm killed 22,000 people—the most ever to perish in an Atlantic hurricane.

Every year from June through November, Southwest Florida weather forecasters keep watchful eyes on the tropics, waiting to see if a swirling dervish will rise up and howl towards our shores. But along the coastline from Tampa to Sarasota, we’ve been fortunate. Sarasota County has had some close calls, but only one direct hit in recent memory, when a hurricane with 100 mph winds passed through Venice in 1944. Tampa has been struck by only two major hurricanes since records have been kept, one in 1848 and one in 1921.

Prevailing east-to-west winds protect our region from most hurricanes, says Masters. “Steered by those winds, [hurricanes] usually strike Florida while traveling east to west, meaning they have to traverse the width of Florida before getting to Sarasota,” he says. “Hurricanes get their energy from the warm waters of the ocean, so storms traversing across land to Sarasota always weaken dramatically. On the other hand, when an uncommon flow of steering current airs results in a hurricane hitting Sarasota from the west or southwest, a much stronger storm with a big storm surge can result.”

In 2010, the Tampa Bay Regional Planning Council published a report detailing the possible effects of just such a storm, one coming ashore near Tampa with 160 mph winds and a 26-foot storm surge. A Category 5 hurricane like that could cause 2,000 deaths and $250 billion in damage. And what if the storm were even worse?

“We might need to invent a Category 6 for Grey Swan storms,” wrote Masters on his blog.

If history is any guide, Grey Swan storms, although vastly more dangerous and destructive, would have at least one thing in common with typical hurricanes: a reluctance by residents to leave their homes.

“There is no hunkering down. Get out!” says Sarasota County chief of emergency management Edward McCrane when asked what advice he would give residents facing a Grey Swan storm. Thousands might die otherwise. But as McCrane knows, locals—especially those who have lived through years without a disaster—are slow to leave even when emergency managers order them to. And evacuation is easier said than done. Imagine the gridlock that would seize I-75 if a significant percentage of the county’s 370,000 people took to their cars.

Pinellas County emergency manager Sally Bishop admits to being haunted by the evacuation issue. “I’ve got 900,000 people to get out of Pinellas County,” she says. “But we can’t just send people away. Where can they go?” To head south would be to head into the storm; bridges to the east would be impassable; and the northern route, through Clearwater, would mean sharing the road with 100,000 more evacuees.

Richard Collins, the county’s emergency service director, agrees that evacuation is a huge challenge. “From Sarasota down to Collier [County] is the most difficult area in the world to evacuate,” he says. And, he adds, “We’d have to do it days in advance. We’re looking at blue sky, beautiful weather, and we’re warning people they have to evacuate for a threat they don’t see yet.”

Collins and McCrane say they’re working with inland and east coast counties to develop a regional plan. (In the meantime, they suggest that in the event of an evacuation order, residents should consider using east-west state roads 64, 70 and 72, especially if traffic and flooding make I-75 and U.S. 41 impractical.) They’re quick to add that they don’t anticipate a Grey Swan storm leaping to life and whirling into Sarasota anytime soon. With the born caution of emergency managers everywhere, however, they note that even a less-than-worst case scenario could be bad enough.

Any hurricane—and even tropical storms, as those who remember how Gabrielle cut a swath of destruction through the region in September 2001—can be dangerous, they warn.

“If a 215 mph hurricane were heading for us, that’s going to be a bad day,” McCrane says. “But if we have a 90 mph hurricane and people don’t evacuate when we tell them to evacuate, it’s going to be just as bad for us.”