That Tim was willing to operate without a safety net for so long is an enigma to some. Even more vexing is that he saw his fate coming, at least on some level: “Somebody’s gonna get bit,” he had said, presciently, even as he pushed his limits further. The contradiction perhaps speaks to the double-edged nature of obsession, and how it both drove and doomed Tim. His devotion made possible unheard-of feats of scientific discovery, but it also inured him to the risks he was accruing—as he grew calm and comfortable under the anvil, as his son entered the same perilous territory. The effect of his own expertise was a kind of tunnel vision. Looking out, Tim was keenly aware of the looming threat, but blind to his own proximity.
After so many years of inching closer, he couldn’t appreciate how close to the dragon he had finally sidled. He could reach out and feel its presence—the warmth of its breath, the tick of its pulse. He could grab ahold of it, and it of him.
On May 9, 2016, Tim Marshall stared down a tornado near Sulphur, Oklahoma, watching for the left or right drift. He dropped his last remaining pod on a country road and fled with the wind at his heels. Based on the surrounding damage and an examination of DOW radar data, the pod caught the outer edge. That day, Marshall claimed one of the closest hits in history—and the first since Tim’s death. The scientific effort marched forward, one step more, one step wiser, though perhaps without the same verve. It was no Manchester; it wasn’t a core strike.
As difficult, perilous, and often frustrating as this work can be, it’s more important now than ever. Recent research into our changing climate, and its effect on severe-storm activity in North America, is sobering yet inconclusive. We know that as the oceans warm, increased rates of evaporation will flood the skies with elevated concentrations of moisture. This means more instability, more CAPE, more fuel for violent storms. But there are also studies that project an attendant decrease in wind shear. Tornadoes require converging air masses to form. Most climate scientists speculate that the result may be a lower overall number of tornadoes.
But there’s an important catch: when the elements do align, the tornadoes and the outbreaks that result may be much, much worse. One analysis indicates that this is already happening.
Two statisticians, Elizabeth Mannshardt of North Carolina State University, and Eric Gilleland of the National Center for Atmospheric Research, recently compiled more than forty years’ worth of atmospheric soundings, focusing primarily on the two biggest supercell indicators: wind shear and CAPE. When they plotted tornadic storms over these years, what they found was alarming. The “return period,” or the average amount of time that elapses between a given extreme tornadic event, appears to be decreasing. In other words, the extremes are becoming less rare, a trend line that may well worsen.
As case studies, Mannshardt and Gilleland examined two recent tornadic events: the May 20, 2013, Moore, Oklahoma, supercell, and the twister that claimed the lives of Tim, Carl, and Paul near El Reno. According to their analysis, these storms are exceedingly rare, situated somewhere near the outer edge of statistical probability. Historically, Moore should only see a tornado of that ferocity once every 400 years. But between 1999 and 2013, the city has been struck by two historic EF5 tornadoes and one EF4.
The El Reno event is even more exceptional. For this storm’s atmospheric conditions, the return period is once every 900 years. Tim would never have chosen this fate for himself, his son, and Carl, but he would almost certainly have been thrilled that he was present for a nearly once-in-a-millennium event.
The statistical model on which these figures are based, however, assumes a constant climate over the last forty-two years—which is not the case. When the model allows for a steady increase in certain parameters, such as atmospheric instability produced by warming oceans, the research indicates that such massive storms are likely to recur far more frequently as the climate changes.
There is hope, as research into massive tornadoes continues. One of the most promising new research initiatives involves TWISTEX’s own Bruce Lee and Cathy Finley. With TWISTEX at loose ends, they partnered in 2014 with a scientist and computer whiz on a first-of-its-kind project. Leigh Orf, a researcher at the University of Wisconsin at Madison, had just made a major breakthrough, using raw atmospheric data and one of the fastest supercomputers in the world, to simulate a supercell and EF5 tornado from birth to death—simply by feeding it a primed atmospheric sounding and letting a state-of-the-art physics program run its course. The wedge in his uncannily lifelike visualizations bears an unmistakable resemblance to the real May 24, 2011, event on which it is based. Orf has brought Lee and Finley aboard because he now needs field scientists who’ve witnessed the beast in the flesh; his data is so formidable and in such high resolution that he needs experts who know what to look for, and where.
The three now have on their hands the answer to every question a scientist could possibly ask about a single monster tornado. Represented by the ones and zeros of computer code are all the internal currents that mobile radar and even in situ probes could never see. As of this writing, the trio are still hard at work teasing apart and reverse engineering the sky’s most complex riddle. The next superstorm they plan to simulate is the one that killed their friends in El Reno.
EPILOGUE
LORETTA YOST’S SPEECH is as austere as the plains—clipped, a little formal, belonging to another century. She wears a simple cotton dress, a black cardigan, and a black Mennonite prayer
