When Franklin Lombardo arrived at the National Institute of Standards and Technology (NIST) in the summer of 2010 as a newly-minted PhD in wind engineering, he expected to spend his time there developing wind maps of the US.
NIST's wind maps are used to calculate potential wind loads on new buildings, and ultimately help to support the development of building codes. The maps need to be refreshed regularly as science, technology, and the climate change.
Nine months in to Lombardo's job, however, everything changed. On the evening of Sunday, 22 May 2011, a multiple-vortex tornado touched down in the city of Joplin, Missouri. In less than an hour, the tornado levelled over 500 structures, caused nearly $3 billion in damage, and killed 161 people—bringing another of NIST's responsibilities to the fore.
Following the World Trade Center collapses and Pentagon attack on 11 Sept. 2001, NIST was authorized to conduct technical investigations of building failures in these and other major disasters, with the aim of issuing reports and making recommendations.
It had only carried out one such investigation since then, into the 2003 Station nightclub fire in Rhode Island that killed 100 people. As the deadliest and most destructive tornado in US history, Joplin now looked likely to be NIST's third. (Hurricane Maria and, most recently, the condominium collapse in Surfside, Florida, would be the agency's fourth and fifth investigations).
"NIST goes through a criteria for every disaster event that includes the loss of lives and people affected," Lombardo told IEEE Spectrum in a phone interview. "It had already been an active tornado year, but when Joplin came along, it was a singular event. By the next morning, we had some idea that were going to go out and do a preliminary reconnaissance."
Time is crucial when responding to a disaster, as rescue teams work around the clock to locate survivors and restore normality. By Tuesday morning, when Lombardo and three NIST colleagues arrived in Joplin, the roads had already been cleared. "The community obviously wants to get back on its feet," said Lombardo. "But from an engineering point of view, an undisturbed scene is best to understand what happened, so the quicker you can get out there, the better."
" had already been an active tornado year, but when Joplin came along, it was a singular event."
Travelling with Lombardo were another wind engineer, a structural engineer, and a social scientist, all NIST staffers. Lombardo had not yet received training for operating in a disaster zone, and could not rely on the sophisticated lidars and drones that descended on Surfside recently to help understand that building's failure. "In 2011, the technology was there, but NIST didn't employ it and probably didn't have the expertise to really carry it out," said Lombardo. "Once we first got on the ground, we adapted, took stock of what was going on and went from there."
NIST's reconnaissance involved touring destroyed buildings, taking photos, and, crucially, speaking with residents and survivors. "If people can talk you through what they experienced—did the windows blow out first? What happened to the roof? That can be hugely beneficial to understanding how a structure progressively collapses," said Lombardo.
After the four-day reconnaissance mission was over and NIST decided to push ahead with a full technical investigation, a meteorologist joined the team and the hard work really began. Over the next three years, the team compared its photos with structural drawings of hundreds of structures that had been severely damaged or destroyed, gathered as much meteorological data as possible, and sought out other sources of information.
"We ended up with surveillance videos from some of Joplin's schools, as well as high resolution aerial imagery that helped us estimate how strong the winds were [about 281 kph—or 175 mph], based on the fall patterns of tens of thousands of trees," said Lombardo.
Ultimately, the NIST team analyzed hundreds of interviews to extract common threads and reconstruct the path and impact of the storm. "I used some of that information to help the wind field model that I was building to compare to structural damage," said Lombardo. "When actual measurements are so scarce, you turn to anything you can to try to better understand what happened."
The interviews also helped reveal some social causes of the tornado's high death toll. There was evidence of high false-alarm rates among tornado warnings for Joplin, confusion about the emergency communications systems, and even a myth that Joplin was immune to direct tornado strikes.
Lombardo left NIST in 2013 for academia—he is now an assistant professor at the University of Illinois, Urbana-Champaign in the civil and environmental engineering department—but continued to work on the Joplin investigation.
In 2014, NIST issued its final report into the tornado, concluding with a list of 16 recommendations to improve measurement and characterization of tornado hazards, come up with new methods for tornado-resistant building design, enhance guidance for community sheltering, and improve and standardize emergency communications.
This photo from the NIST final report shows the destruction the F5 tornado caused at Joplin's East Middle School—including complete loss of steel roof deck, disconnection and collapse of the first two bow-string steel trusses, and collapse of 9 out of 11 tilt-up panels of the west wall. NIST
"The previous thinking was that tornadoes are rare, they're small, and the chances of one hitting an individual structure are very slim," said Lombardo. "The biggest thing from our report was the understanding that there's more risk there from tornadoes than anyone previously thought."
The latest design standards will not only include the revised tornado maps that Lombardo was meant to work on at NIST but also a specific tornado chapter that requires builders to take extreme weather events into account.
"We simply didn't design for tornadoes before," said Lombardo. "And not everybody will need to in the future. But there are areas where tornadoes have to be considered and, if you do need to design your structure to withstand tornado loading, you'll now have some guidance to do it."
It has taken ten years from the tragedy of Joplin for changes to find their way into building codes and standards. Does that mean it could take another decade for lessons to be learned from Surfside?
The latest investigation is already well underway, with NIST setting up a data portal to crowd-source photos, videos, and other documentation from the public. "A lot of people also now have Nest or Ring camera footage that could be hugely beneficial to understanding causes of failure," said Lombardo. "This was all just starting to be seen as a potential benefit to our investigation 10 years ago, but the sheer volume of data wasn't there."
Even with the advantage of new technologies, Lombardo cautions against expecting results from the Surfside investigation anytime soon: "Surfside was a single structure, which may take less time, but it's going to be a while before we find out anything. The public always want to know the causes right away, but technical investigations just don't lend themselves to quick solutions."