When Florida International University turns on the “Wall of Wind” in their aircraft hangar-turned-engineering lab, the 12 giant fans generate the force of a major hurricane. Within seconds, the walls and roof of their target, a scale-sized model house, can be ripped away and hurled into a web-covered field.
This test and others tell engineers at the university’s Institute for Extreme Events how to design and build structures that can withstand the 157-mph winds associated with a first-class Category 5 storm. But now, as climate change threatens to worsen storms, scientists plan to build a new hurricane lab to test what some are unofficially calling Cat 6.
“I want to see research and testing in the 170-190 mph range. Much of the research takes place at lower wind speeds, but I have to switch to extreme wind speeds because that’s where nature is going,” says Richard Olson, director of the institute. “Who wants to say 20 years from now, ‘Ya — I knew this was coming, but we didn’t do anything about it.'”
Two recent storms underscore this point: Hurricane Patricia hit Mexico in 2015 after reaching winds of 215 mph, and Hurricane Dorian slammed into the Bahamas in 2019 with winds of 185 mph.
With a $12.8 million grant from the National Science Foundation (NSF), the university plans to design a lab capable of testing 200-mph high winds and add equipment that will create life-size model homes with 20 -Foot storm surges can flood.
“We will have a facility that can simulate this area. It will bring new capabilities to the US and the world,” says Arindam Gan Chowdhury, civil engineer at FIU and lead researcher on the project.
Better testing could save more homes
This year, meteorologists are forecasting an above-average hurricane season for the third year in a row. Just a day after the season officially started on June 1, South Florida was inundated by over a foot of rain that would eventually intensify into Tropical Storm Alex. Last year’s hurricane season was the third busiest on record, the most active after 2020.
The science behind the effects of climate change on hurricanes is becoming clearer. A report by the Intergovernmental Panel on Climate Change (IPCC) released in August found that warming temperatures will make hurricanes slower and rainier, and more likely to intensify rapidly if a storm increases wind speeds by 35 miles per hour in just 24 hours .
On the Saffir-Simpson scale, category 5, the highest, has no upper limit. Scientists disagree on creating a Category 6; Some think another classification might draw too much attention to the wind, given that 90 percent of hurricane deaths in the United States result from storm surges and flooding, which threatens about 24 million people.
The FIU’s Wall of Wind Laboratory, built in 2012, was in response to Hurricane Andrew, the catastrophic Category 5 that struck south Florida in 1992 and caused $25 billion in damage. The recovery was long and painful; Florida’s hurricane building codes, updated after Andrew, are the strictest in the country to date, according to the Insurance Institute for Business and Home Safety.
Since then, the engineers of the FIU have continued to advance the science of protecting structures. You’ve learned how small upgrades can help secure homes against high winds. Serrated ring-shank nails, for example, hold up better than smooth nails; four-sided roofs are most likely to remain; and metal hurricane straps help attach roofs to walls.
The facility is the largest of its kind in the US capable of testing Category 5 winds. To generate such speeds requires fans two meters in diameter and weighing 15,000 pounds each, the weight of two trucks.
Even at only 100 km/h the roar of the fans is so loud that conversations have to be shouted. During a May test funded by the Florida Division of Emergency Management, engineers set up a two-foot-tall plastic mock-up of a mobile home in front of fans to study where winds put the most pressure on prefab homes. Wind blew across a floor covered in metal flaps and blocks that simulated buildings and trees, creating turbulence. As the model spun on a disc in the center of the room, a tangle of black wires inside measured how much pressure was being applied to the walls, roof, and corners.
Laboratory manager Walter Conklin carried out the experiment via live transmission from a mobile home right in front of the facility’s entrance. “Everything shakes at 250 km/h [in the trailer]. You feel it,” he said. To produce 200 mph at the new facility, they need twice as much electricity, he says.
For now, the new FIU facility is run by NICHE, mercifully short for National Full-Scale Testing Infrastructure for Community Hardening in Extreme Wind, Surge, and Wave Events. It will be 40 feet tall, Chowdhury says, twice the height of the Wall of Wind house to test two-story buildings.
“We will know what survives and what doesn’t,” says Chowdhury. “Imagine the year 2050 and testing at this facility has shown us that ‘at 200 mph these types of structures can withstand these winds but this one cannot’ and a storm forecast is even close to that wind force. then we know what works.”
Eight other universities and a private company are working together with the FIU on the prototype. NICHE will combine personal observations at disaster sites, computer simulations and experiments like those at FIU to improve understanding of building design.
“Having a facility like the FIU that can test an entire structure and how it will withstand water and wind — that can save lives,” said David Merrick, director of the Emergency Management and Homeland Security Program at Florida State University in Tallahassee.
It will also likely redefine the standards for building storm-proof homes.
(Learn more about how scientists predict storm surges.)
Stronger houses for stronger storms
“Eventually there will be a greater need for innovation and radical changes in the way we build,” FIU civil engineer Ioannis Zisis says via email.
“Radical,” he concedes, sounds extreme, but it doesn’t mean everyone in South Florida needs to build a bunker. He describes concrete-reinforced walls, concrete roofs, and covers that protect windows from flying debris.
But turning that science into on-site DIY will be another challenge, says Tracy Kijewski-Correa, a civil engineer at Notre Dame University and co-lead researcher at NICHE.
Despite the threat of storms like Hurricanes Patricia and Dorian, hundreds of thousands of people have moved to the hurricane zones along the East and Gulf Coasts over the past decade. Florida, in particular, has seen a boom in population growth recently, according to US Census data.
In a study published in 2019, Kijewski-Correa found that even those coastal residents who see climate change as a growing threat are unlikely to believe that their homes will be destroyed by a storm.
Kijewski-Correa wants hurricane-prone communities to modernize their homes faster and adopt market-based measures like tax incentives to encourage residents to make life-saving improvements to their homes.
At best, she says, building codes help individuals survive storms, but homes still face costly structural damage. Implementing better upgrades can help save lives and livelihoods.
“If we don’t want these losses in a changing climate, we have to stop being satisfied with survival,” she says.