Yet action to prepare for such a storm has been slow. In Houston, the most popular suggestion is something called the “Ike Dike,” a seawall along the outer coast that might prevent a storm surge. But many experts think the Ike Dike would be insufficient, and in any case, the seawall still hasn’t been built.

“I think everyone in the community is in agreement here—politicians, engineers, people in leadership positions—they’re all in agreement that we need to do something. But it’s been seven years and really very little has been done,” Rice’s Phil Bedient, co-director of SSPEED, told me two summers ago. “I’m actually fairly optimistic that something will be done, because it needs to be done. Now, whether that will be done before the next big one hits?”

Last year, he told ProPublica, “We’re sitting ducks. We’ve done nothing. We’ve done nothing to shore up the coastline, to add resiliency … to do anything.”

Bedient was only slightly more sanguine on Thursday. “I don’t think much has been done to mitigate flooding in the past two years,” he wrote in an email. Bedient pointed to Project Brays, a flood-reduction effort, as a positive step, but he noted that the work only protects part of the city. “No other major projects have been undertaken.”

Despite the havoc it wreaked, Ike was in many ways a bullet dodged for Houston, since it didn’t hit directly. A century earlier, in 1900, a storm struck Galveston directly, producing almost unimaginable destruction. Historians now estimate that between 6,000 and 12,000 people were killed.

A hurricane of that size today would have a very different effect. Because of the development of tracking technology, no storm would ever strike with so little warning, which means it’s unlikely any hurricane in the U.S. will ever be so lethal. But 117 years of development in the region mean that the big storm—whether it’s Harvey or a future one—will be more complicated and have farther-reaching effects.

For one thing, many more people now live in the path of a storm. Corpus Christi is a crucial oil-refining center, and the nation’s fifth busiest port. Add in the Houston Ship Channel, another major petrochemical industry center, and the risk of an environmental disaster or a major disruption to energy supplies gets larger. Harris County, home to Houston, is the nation’s second fastest-growing county. Population growth brings with it new developments, some of them in vulnerable places. NASA’s Johnson Space Center sits on low ground on the west side of Galveston Bay in Houston.

Industrial installations in the Houston Ship Channel are built to withstand a storm surge as high as 15 feet. Ike’s storm surge was 13 feet. But SSPEED found that a category 3 storm could produce a surge as large as 25 feet. A 22-foot surge could spill 59 million gallons of crude oil and other chemicals; a 24-foot surge could spill 90 million gallons. “The damage caused by such an event would be devastating and could easily become the worst environmental disaster in U.S. history,” Rice’s Baker Institute for Public Policy concluded in 2015.