‘Cat 6’ Hurricane Simulator With 200 mph Winds

MELBOURNE, Fla. (AP) — The Category 6 hurricane’s howling winds accelerate to a startling 200 mph in Miami, mercilessly pummeling a two-story wood-frame house until the roof tears off and the rattling windows explode.

And a towering 20-foot storm surge spawns battering waves, swamping the structure and shoving it off its foundation like a doomed dollhouse.

Sounds like a scene from a sci-fi disaster movie.

But with real-world Atlantic hurricanes pushing the limits of the Saffir-Simpson Hurricane Wind Scale, Florida International University researchers envision a future mega-wind-water simulator that tests how building components would react under Cat 6 conditions.

FIU’s Extreme Events Institute already operates the 157-mph Wall of Wind hurricane simulator, where experimental results have been applied to the Florida Building Code. Now, the school is spearheading a $12.8 million National Science Foundation partnership to design a larger national testing facility capable of generating 200 mph winds.

In destructive tandem, this Cat 6 project will incorporate a water basin that can churn up to 20 feet of storm surge.

“We used the 200 mph mark because there are more and more events lately that they call stronger-than-Cat 5,” said Ioannis Zisis, co-director of FIU’s Laboratory for Wind Engineering Research.

“This is a very ambitious project in terms of combining different hazards. So we want to do the wind, but we want to add also the storm surge, the water component,” Zisis said.

“So it’s a very complex project, a very complex facility — that is going to be also very expensive,” he said.

FIU’s academic partners on the project: University of Florida, Oregon State University, Stanford University, University of Notre Dame, Georgia Institute of Technology, University of Illinois at Urbana-Champaign, Colorado State University and Wayne State University. Aerolab, a Maryland wind-tunnel company, is the principal industry partner.

Design work began in January on the future simulator, which is technically named NICHE (National Full-Scale Testing Infrastructure for Community Hardening in Extreme Wind, Surge, and Wave Events).

Zisis said researchers will spend the next four years designing the enormous facility _ and it is “critical” that they make a series of key decisions within the first six months. Further details on construction, such as funding sources, remain unknown.

Should we create a Category 6 hurricane?

Richard Olson is director of FIU’s Extreme Events Institute. In a 2019 FLORIDA TODAY guest column, he lobbied for creation of a new Category 6 hurricane _ with fearsome sustained wind speeds of 180 mph or higher — atop the five-level Saffir-Simpson Hurricane Wind Scale.

Olson pointed out historical storms such as the 1935 Florida Keys “Great Labor Day Hurricane” (sustained winds of 185 mph), Hurricane Allen in 1980 (190 mph), Hurricane Wilma in 2005 (185 mph), Hurricane Irma in 2017 (180 mph) and Hurricane Dorian in 2018 (185 mph).

“Opening a discussion of at least a Category 6 for Atlantic Basin storms has some urgency. Climate-change scientists are arguing for increasing numbers of more intense storms in coming decades,” Olson said in his 2019 column.

“That is, storms with sustained wind speeds of 180 mph should no longer be viewed as extremely rare,” Olson said.

Federal Emergency Management Agency Administrator Deanne Criswell touted the FIU project during an April 13 National Hurricane Center keynote speech in Orlando.

“What if we could simulate a Category 6 hurricane?” Criswell asked the audience.

“This kind of cutting-edge research, this kind of testing capability, is just what we need to meet the nation’s evolving risks. To help us adapt to future conditions. And to help us protect life and property,” she said.

Criswell said FEMA projects U.S. communities that adopt modern building codes will avoid paying $132 billion in storm damages by the year 2040 _ but 65% of counties, cities, and towns have not adopted modern building codes.

FIU’s 157-mph Wall of Wind

FIU’s Wall of Wind is a warehouse-like facility that can create Category 5 hurricane conditions with winds up to 157 mph. Researchers blast sensor-equipped test structures — such as small simulated houses, roofing materials, windows, traffic signals, and solar panels — and create three-dimensional computer models measuring wind forces.

The 8,400-horsepower Wall of Wind is powered by a dozen yellow circular fans, each measuring 6 feet across and weighing 15,000 pounds.

Water outlets also mimic cascading rainfall amounts of up to 8 to 9 inches per hour.

Last year, the NSF awarded FIU a $5.62 million grant to continue Wall of Wind scientific research through September 2025. However, unlike the Wall of Wind, Zisis said the future Cat 6 hurricane simulator will be big enough to accommodate full-sized homes.

“We envision putting in front of the fans a two-story building, on a turntable,” Zisis said.

“Right now, we can test a smaller structure. We can test building components, solar panels, things like that. But the actual structure that we can accommodate in front of the Wall of Wind is like a 10-by-10-by-10 cube,” he said.

“The past 30, 40 years, most of the things that we have in the building code and the wind tunnels came from small-scale studies. And they’re very, very useful. Very scientific, and they’re very important. But when we test at full-scale, we learn even more,” he said.

“Right now, we’re more into component testing in the Wall of Wind because we’re restricted by the size. We can’t see how the wind load is transferred from the exterior of the building down to the foundation. That is something that we envision doing with a new facility,” he said.

So how big would FIU’s Cat 6 simulator have to be? Miami New Times reported it could be comparable in size to a small football stadium, while the Washington Post reported the wave basin may measure 200 feet long.

Nobody knows at this early stage, Zisis said. During the $12.8 million design effort, Zsis said researchers will construct a smaller-scale prototype simulator at FIU to verify and validate their assumptions.

“The small-scale replica of this huge facility is going to be like a similar size to the Wall of Wind, more or less,” he said.

FEMA: Expect extreme climate events

During her National Hurricane Conference speech, Criswell said the United Nations Climate Science Panel fears that unless global greenhouse gas emissions peak by 2025 and are cut 43% by 2030, the world will likely experience extreme climate events.

“Now, does this information cause us to sink back in our seats? Perhaps. But I encourage all of us in this room to embrace this information and not discount it as alarmist,” Criswell told the audience.

“We have the world’s top climate scientists working hand-in-hand, nation-to-nation, to arm us with the best information and the best data available to help us save lives and protect property. So we need to leverage this data and act,” she said.

“Let’s use it to inspire a collective shift to a future-based mindset across all levels of government and all of our communities nationwide. Let’s use it to anticipate, plan for, and mitigate risks that are 10, 20, 30 years in the future,” she said.

Jim Bell is director of operations with the National Storm Shelter Association. A former Fort Lauderdale resident, he was president of the Gold Coast Chapter of the Door and Hardware Institute when he served on a committee that helped strengthen the Florida Building Code after Hurricane Andrew struck in 1992.

“The part that’s very intriguing is the storm surge. Because that’s even more severe than the winds,” Bell said of FIU’s future Cat 6 simulator.

“When we’re talking the wind speeds that they’re looking at, you’re going to have to do more with windows and doors and such. Because once the wind gets inside the building, the building pressurizes — and it’s popping the roof off or popping windows out,” Bell said.

“As the pressure builds up, it’s looking for another place to push out. That’s what creates the damage, the exploding effect,” he said.

Saffir-Simpson Hurricane Wind Scale

Structural-damage details of the Saffir-Simpson Hurricane Wind Scale, per the National Hurricane Center:

Category 1: 74 to 95 mph. “Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.”

Category 2: 96 to 110 mph. “Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks.”

Category 3: 111 to 129 mph. “Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.”

Category 4: 130 to 156 mph. “Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.”

Category 5: 157 mph or higher. “A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.”

About the photo: In the aftermath of Hurricane Ida, bowling balls sit in a rack at the heavily damaged Bowl South of Louisiana Tuesday, Aug. 31, 2021, in Houma, La. (AP Photo/David J. Phillip)