If a strong hurricane hits South Texasjust right, an epic storm surge of more than 25 feet will barrel through the Houston Ship Channel, knocking over oil and hazardous materials storage tanks, crippling the nation's busiest foreign tonnage port and its largest petrochemical complex in one blow. Even a monthlong closure of the channel would cost the national economy more than $60 billion—no doubt drawn from federal coffers—before counting rebuilding and environmental cleanup costs. Not to mention the possibility that hundreds could die in such a storm. 

The region's highways already can't handle the current evacuation load of more than 1 million people, and that's before an expected 500,000 more move to the area over the next two decades. In the wake of hurricanes Katrina and Rita, and Houston's own Ike—a Category 2 storm that did not hit the city directly, yet still wrought $30 billion in damage—such scenarios are emerging from researchers and frightening politicians just now realizing how vulnerable the area has become. A Katrina-like storm in Houston would undoubtedly produce Katrina-like damage or worse, given the larger population and richer infrastructure of a much bigger metropolitan area. Those prophecies and others come from a new study from Rice University (pdf), which puts the total damage estimate upward of $100 billion. Its release comes at the beginning of a hurricane season that experts expect to be more active than most in the Gulf of Mexico. 

In the Houston area, meanwhile, politicians and academics are debating the merits of what locals call the "Ike Dike "—a massive series of flood walls and gates that could stretch 60 miles and, conservatively, cost $3 billion. The dike competes for support and money with more amorphous "nonstructural" protection measures, including fortifying coastal wetlands and limiting development, which ultimately may prove more important. The key nonstructural measure is the most obvious and yet the most controversial: Stop building in flood plains. 

"Right now, you can still build a million-dollar house on the west end of Galveston Island"—one of the most hurricane-prone areas in America—"and get flood insurance," said one of the study's authors, Jim Blackburn, an environmental attorney and professor at Rice University. Since Ike in 2008, six counties in the flood zone have formed the Gulf Coast Recovery and Protection District, a nascent effort to examine long-term solutions. Houston lawyer and businessman Bill King helped lead the push for its creation. He says most Houstonians still don't understand the true scope of the problem, as many are still looking for one big project as a cure-all. 

"A lot of people are getting into an either/or kind of debate, and that doesn't make any sense—we need both structural and nonstructural protection," he says. "We have a million people already living in the surge zone, and 40 percent of the jet fuel used in the United States is refined in the surge zone. . . . This is something we're going to be fighting from now on, and we have to come to terms with that, unless we're all going to pack up and move to the Rockies."