Two million more people have taken up residence in Florida since a hurricane last hit in 2005. That growth, concentrated along coastal areas likeliest to be washed away by a storm, means the state is in many ways more vulnerable than ever to catastrophic damage from a tropical hurricane. As another hurricane season gets under way today, emergency managers fear Florida's newcomers are ignorant to the dangers of hurricanes and veteran residents are afflicted by complacency after an unprecedented storm drought.Elegant homes and high-rise condominiums have sprung up along eroding shorelines in places like Miami Beach, putting billions of dollars in property at risk. Public and private insurance programs would be pushed to the limit by a major storm.Were a big hurricane to slam Miami or Tampa Bay, the damage would easily reach $100 billion, said Charles Watson, a hazards damage analyst."The bottom line in Florida, the polite way I can put it is: You're doomed," he said.Will people evacuate?Florida in the past few decades has experienced explosive population growth of residents young and old. With 20 million people, it is now the nation's third-most populous state.Pasco and Hernando are among the counties that saw a major influx as developers carved neighborhoods out of farmland. From 2000 to 2010, both grew by more than 30 percent. Even in Pinellas, where the population remained relatively level at 929,000, the county saw significant churn, with an estimated 46,000 people moving in each year, replacing those who moved or died.A number of these new residents have seen hurricanes only from their television or computer screens. One big unknown: Will they evacuate when told?"The state of knowledge of the typical Floridian through no fault of their own is almost minimal," said Peter Muller, a geography professor at the University of Miami.Consider that the last hurricane in Pinellas spun through in 1921, a Category 3 storm that killed six people, but caused less than $10 million in damage. Today, a county estimate shows, the cost would be measured in billions, with nearly 6,000 households displaced. Even a Category 1 storm would cause more than $2 billion in damage around Tampa if it were to strike there directly, according to estimates from Hillsborough County, where more than 110,000 structures (most of them residential) sit in an evacuation zone.Upgraded building codes that call for shatter-proof windows and hefty wind resistance mean new construction stands a better chance of holding up in a storm."The things that we are building are going to be more resilient than they have been in the past," said Bryan Koon, the state's emergency management director."Building codes … have actually reduced the (potential) damages (from a hurricane)," said Graham Tobin, a geosciences professor at the University of South Florida.Upgrades, though, have limited reach, as many structures predate the standards. More than half of the homes in Pasco were built before the Florida Building Code was enacted in 1994, according to the county.Tampa Bay is also full of mobile homes — more than 100,000 across Pinellas, Pasco, Hillsborough and Hernando. Even with improved durability (the result of Hurricane Andrew, which left chewed-up double-wides strewn across South Florida) such structures are often broken up by cyclones and tossed about like autumn leaves in the wind. A 2013 state analysis found that there were more than 850,000 mobile homes in Florida.Building stronger, more expensive structures is not always the best way to mitigate financial loss, according to Watson, who has worked in hazard modeling since 1989 and has advised a panel that seeks to ensure Florida adequately assesses its risks from hurricane damage. For instance, he said, the destruction of a modest, older home along the water still costs less than repairing a million-dollar mansion that is damaged 25 percent.A more pragmatic view, he said, would be to assume that "if something is on the coast, it's going to get knocked down."Wind, then waterAfter a hurricane, when the wind dies down, the water begins to rise. In Tampa Bay especially, storm surge poses a significant threat. If a strong hurricane hit, 20 feet of water could rush into downtown Tampa, flooding miles of land and pulling splintered homes out to sea when it receded."We can make things safer from the wind," said Harold Wanless, a geology professor at the University of Miami, but "there is so little you can do to make something safer from the storm surge. The risk is just huge."Miami-Dade County is arguably the most vulnerable. If a Category 4 storm hit Miami, damage might exceed $125 billion, said Dennis Feltgen, spokesman for the National Hurricane Center.Part of that expense is due to the gush of shoreline construction, which has carried on undaunted even as high tides routinely encroach, a frequent reminder of rising seas. Interlaced with all the danger is the nation's flood insurance problem. Rates in recent years rose when federal subsidies were removed because of billions of dollars in debt looming over the National Flood Insurance Program. But after public outcry, Congress has delayed some of the steepest increases.The flood insurance program is managed by the Federal Emergency Management Agency, which is itself wallowing in debt so great that a report last year said FEMA could pay only interest on what it owes.Christian Cámara, director of the free market R Street Institute in Florida, said subsidized flood insurance has exacerbated the coastal population crunch, too."When you have subsidized insurance rates, especially in the high-risk areas, it encourages irresponsible and risky development," he said.Cámara said Citizens Property Insurance, Florida's insurer of last resort when disaster strikes, has bolstered its coffers during the decadelong hurricane drought. Part of that leveling out, though, is the result of Citizens dishing off customers to small and unproven insurers.If a hurricane struck today, Cámara said, Citizens would likely cover all claims, but be depleted for the next storm. Longtime residents need only remember the four hurricanes of 2004 to be worried.Geological specialists say the threat is only going to get worse as Florida continues to grow and the forces of climate change take hold. Many experts expect feet of additional seawater to encroach and swallow parts of the developed coast within decades.A hurricane will almost certainly come much sooner.Times staff writers Susan Taylor Martin and Claire McNeill contributed to this report. Contact Zachary T. Sampson at [email protected] or (727) 893-8804.