There is an old country-and-western song my father liked called “Ghost Riders in the Sky.” My father had been born and raised in rural Oklahoma during the Dust Bowl years and had spent his adolescence working at cattle ranches in Colorado and Wyoming; in his later life he was fond of saying that he had been one of the last of the old-fashioned cowboys, and he often recited scraps of cowboy poetry or retold the spooky folklore he’d heard from the other ranch hands. “Ghost Riders in the Sky” was a perfect example. It’s about a cowboy who has a terrifying vision: he sees the souls of damned cowboys riding through the night in an eternal chase after a stampede of supernatural cattle. One of these spectral cowboys breaks off the pursuit long enough to warn the singer to repent his evil ways, or else, after he dies, he will join them “trying to catch the Devil’s herd across these endless skies.”
I don’t remember my father ever connecting this stampede to tornadoes. But then, he didn’t have to. I made the connection myself the first time I heard him sing the song, and it’s stayed with me ever since. He was constantly telling me scary stories about tornadoes. He made them sound like a regular feature of his childhood landscape. The way he described it, anywhere on the Great Plains, if you raised your eyes to the horizon, you might somewhere in the vast flat distance see a funnel cloud beginning to form. He talked about all the different and bizarre shapes they took: grand swooping curves of impossible architecture, furious little whirlwinds like the clouds of dust above cartoon fistfights. He repeatedly told me about the closest call he’d ever had with a tornado—a blustery summer day when he and his friends had been playing baseball and a tornado had come roaring across the outfield; they’d had to hide in the dugout, clinging to the underside of the bench, to keep from being sucked into the funnel. But his favorite stories were about the nights he and his family had spent cowering in their snug lantern-lit storm cellar as the world outside had torn itself apart in the frenzy of a prairie thunderstorm: at some point his mother would raise a finger for silence, and they’d hear amid the roar of the wind and the crashes and bangs of thunder a sinister new sound, a deep throbbing and a high-pitched shriek like an airplane engine revving up. “And that,” my father would conclude with satisfaction, “was the tornado.”
I was spellbound by these stories, but I was also baffled by them. I never got that clear an idea of what a tornado really was. We lived then in northern Illinois, a place that was supposedly tornado heavy, but I had only seen one unmistakable tornado in my life, and that was in The Wizard of Oz. Few sights in any movie, or for that matter in the real world, have ever scared me as deeply as that. My father had no patience for it, though. He passed through the living room as my mother and brother and I were staring at the television screen in rapt horror, and he lingered only long enough to emit a snort of contempt. “Nah, that’s no tornado,” he said. “You should see a real tornado.”
Each spring the science class at my elementary school would spend a day on the subject of tornadoes. The teacher would show us a filmstrip that had a lot of cartoon images of spiral-shaped clouds looming over prairie farmhouses. There were also photographs of crew-cut men with white shirts, black ties, and horn-rimmed glasses, clustered in muddy fields around weather balloons. But only a few of the images were of actual tornadoes; in those days, the 1960s, a clear photograph of a tornado was as rare as one of a flying saucer.
The filmstrip’s narrator instructed us solemnly on the rules of tornado safety. There was one infallible warning sign that a tornado was coming, he said: the clouds took on a greenish glow. Tornadoes also caused an electrical disturbance that could be picked up by some TV sets, so if your TV screen grew mysteriously brighter during a storm, that was a clear signal a tornado was somewhere nearby. Then he explained why tornadoes were so destructive: there was a near vacuum at the heart of the funnel, so when it passed overhead, the air pressure trapped inside your house burst outward like an explosion. The most sensible precaution you could take, therefore, was to open your windows to equalize the air pressure. After you did so, only then should you take shelter, and the one safe place to hide was the southwest corner of the basement.
The viewing of this filmstrip turned me into a kind of amateur tornado warden. Whenever there was a storm, I kept my eyes peeled for the warning signs. But where were they? Spring after spring, tornado season after tornado season, I never saw a hint of a green glow in the sky. The closest I came to a tornado was one sultry April afternoon when I was twelve: a severe storm came through the Chicago suburbs, and a tornado touched down several miles away. The next day the newspapers ran an amateur photograph: it showed a blurry smear of buildings and streetlights, while against the horizon stood an indistinct gray cone of smoke towering up to the sky like a supervillain menacing a cartoon city. I tore it out of the paper and tacked it up on my bedroom wall, as though it were a wanted poster.
I did reports for school on tornadoes; I had all the key tornado facts memorized so that I could talk about wind speeds and air pressure with the least provocation. One afternoon in late spring when I was twelve, a storm built up in the west, and the sky around it turned a weird sickly yellow. My teacher, who knew about my obsession—pretty much everybody in the school did—asked me seriously whether that color sky meant a tornado was coming. I said authoritatively that yellow skies meant hail; green was the color of tornadoes. It was the proudest moment of my life.
I even had dreams about tornadoes. The dreams were all pretty much identical: they began with a feeling of horrible dread. I knew, with absolute certainty, that a tornado was approaching. I couldn’t see it; nothing about the scene looked sinister; but it was already too late to escape. Sometimes I’d be the only one who knew, and I’d try in vain to warn everybody of the imminence of disaster. It never did any good; nobody would pay any attention to me. The dream always ended the same way: I was standing at a window, looking out at the sky, all hope lost, and just as the tornado was about to appear, I’d wake up.
I think I was at the height of my tornado passion the summer I was twelve. That was when my family went to visit my father’s old home in Oklahoma, where my grandmother still lived. I spent the whole drive there staring at the clouds and expecting each one of them to transform before my eyes into a tornado. But somehow Oklahoma proved to be deficient in tornadoes. The skies were a ceaseless stampede of white cumulus, and some of them did occasionally puff up into thunderheads, but there were no funnel clouds reaching down to touch the earth. The tabletop flatness of the plains was broken by nothing out to the horizon except oil derricks.
I began to suspect that my father had been goosing his memories in order to scare me; he did always like scaring me. The night of our arrival, though, as we sat together on the front porch, a gigantic line of storms came rolling up over the southwestern sky. I had never seen anything in the world so large; it was like a tidal wave about to wash the plains clean. The sight inspired my father with something like nostalgia. This was just the kind of weather, he told me, that in his childhood had sent the whole family scurrying to the storm cellar for the night.
Did that mean there would be a tornado? I asked. It was the wrong question. I couldn’t keep a quaver of fear out of my voice, and however much my father liked to scare me, I was supposed to bear up under it with stoic impassivity. He soon clumped off to bed and left me to the view. I watched for several minutes more as the storm advanced. Little flickers of yellow lightning were bursting silently all along the billows and crests like artillery fire; by the time I went to bed, I could hear the first mutterings of thunder.
Later that night I woke to find that the storm was exploding directly over my head. The thunder was making the walls quiver; the wind was in a fury, and it felt as if necessary things in the house were all bending over and were about to break. Rain rattled the windows like peltings of glass beads. The lightning bolts flared like searchlights. I went stumbling out of bed in a panic and fell forward down the hallway toward my parents’ room. I had the idea that we might have only a few minutes to reach the storm cellar. But at their door I froze; as frightened as I was by the storm, my father scared me more. I huddled up against the doorway and strangely, unwillingly, fell asleep.
That’s where my parents found me in the morning. Neither of them made any remarks about it. If my father had figured out what had happened, there would have been hell to pay, but I caught a break. He and my mother both just assumed I’d been sleepwalking.
That morning my grandmother took me on a little tour of the house and the yard. I expected to find a scene of total devastation, but everything was in its place: all the trees still had their branches, the flowers were charmingly mussed and gleamed with raindrops. My grandmother made no acknowledgment of the storm at all; as far as I could tell, she thought it was just a typical summer shower. She was much more interested in showing off all the improvements my father had been making for her on the property. He had even installed an automatic sprinkler system so she could see her gardens watered while she watched from her favorite chair in the living room.
By the back fence, though, there was a curious antique. The slope of a low green mound under a stand of trees was set with a weather-beaten door, like an escape hatch from a grave. My grandmother explained that this was the storm cellar. I eagerly asked to see it; she was baffled by my interest and seemed rather embarrassed to show me anything so quaint, but she swung the door up with practiced ease. A few crude wooden steps led down into the dark. My grandmother picked up a flashlight that was hanging on a post and was pleased to see that the batteries were still good. As we stooped together under the rooted, cool earth of the mound, she shone the light around for me. There were several shelves that held rows of glass storage jars; the glass was so cloudy and sooty it was impossible to tell what was in them. On one shelf was a box of corroded batteries, a stack of sooty candles, and a fossilized portable radio. In the middle of the dirt floor was a rotting table and a couple of half-collapsed chairs. The whole place looked as though nobody had bothered to take shelter there in decades.
The basics of tornadoes are not especially mysterious. The simplest way to think about them is to picture a pot of water on a stove. The essential thing is that the burners on the stove are heating the pot from the bottom up. This means that a layer of hot water is forming below a layer of cold water. As a result, the hot water is rising up but is being blocked by the cold water above it. That’s an inherently unstable arrangement. At a certain point, as the heat intensifies, bubbles will begin to float from the hot zone through the cold zone to the surface. But these bubbles don’t pop into existence randomly, all through the pot—at least not at first. Instead, a line of bubbles will appear in one specific place and rise up as though deliberately moving in single file.
This line of bubbles is created by a process called convection. “Convection” is a term for the concerted movement of a small group of molecules within the larger shapeless mass of a fluid or a gas. Several different things can cause convection, but one of the most common is heat transfer. In the case of the pot on the stove, the column of rising bubbles is transferring the heat through the cold layer without disturbing the rest of the water. The column is formed in this way because it requires less energy than a diffused heating of all the molecules in the liquid, and the rule in the physical world is that whatever takes the least energy is the thing that happens. (Only as the heat from the burners continues to warm the water does the process of convection at last get overwhelmed, resulting in the general indiscriminate hubbub of a boiling pot.)
The earth’s atmosphere can be imagined in the same terms. Sunlight warms the earth, and the earth radiates the heat back out into the atmosphere; so it often happens that the lowest layer of air is warmer than the air directly above it. Convection columns will spontaneously arise in the atmosphere in order to transfer the hot molecules near the earth into the higher altitudes. These convection columns may take a variety of forms—the most dramatic and violent being the tornado. A tornado can be thought of as a last-ditch safety valve; it comes into existence only when the atmosphere is growing catastrophically unstable. It’s a kind of emergency self-regulating mechanism that funnels huge volumes of hot air upward as fast as possible and restores the atmosphere to equilibrium.
Tornadoes can, in theory, form anywhere, and they have been observed all over the world (on every continent except Antarctica). But they are most common in the American prairie states. This is because of a fluke of geography. The extreme atmospheric instability that gives rise to the tornado generally happens only when a very large area of hot humid air is overrun by an equally large area of colder drier air. On other continents, the mountainous terrain tends to scatter flowing air masses into confused and irregular forms, but in the central plateau of North America, where the flat landscape extends for thousands of miles in all directions, vast air masses come into contact with each other with a kind of abstract purity as though in a continent-wide experimental laboratory. More than a thousand tornadoes touch down in America every year. This may seem like an appallingly large number, but in fact almost all these tornadoes are weak and brief-lived. The average tornado is less than a hundred yards wide, with winds well under a hundred miles an hour; it skims across the ground for a mile or two and dissipates without doing significant damage. Even in the area of the country where tornadoes are most common—Oklahoma, Kansas, Iowa, the region known as Tornado Alley—a really violent tornado is rare. My father’s stories aside, the truth is that the majority of people in Tornado Alley go their whole lives without so much as glimpsing one.
The history of the American interior is in part a history of tornadoes. It’s a curious kind of history, though, in that it consists largely of obliviousness and denial. The truth is that while midwesterners are afraid of tornadoes, and lots of them grow up as I did, obsessed with them and having recurring nightmares about them, the Midwest has been settled, developed, and generally overbuilt under the working assumption that tornadoes don’t pose any serious danger. Simple shelters from tornadoes by and large do not exist. The advice about hiding in a corner of the basement, even if it were valid (which, as it happens, it isn’t), can’t be put into practice when the typical midwestern suburban house doesn’t have a basement. And while storm cellars used to be common in the rural Midwest, many—perhaps most—have fallen into disuse, and few new ones are built. Those who are frightened of tornadoes find themselves in a situation like that of my recurring nightmare, of trying to alert people to a danger they won’t recognize.
To the tornado obsessed, the very thing that makes everyone else so complacent is just what’s so frightening: the tornado’s elusiveness. It’s not just that tornadoes are rare. It’s that one can happen right in front of you and you still might not realize what you’re seeing. They flash past with little or no warning. They can arrive hidden within curtains of falling rain or occluded by clouds of dust and debris. Some have moved at more than sixty miles an hour and have skimmed through entire towns before anyone outside the immediate damage zone even realized they were there. Sometimes it’s only the amount of wreckage afterward, and the confused memories of the survivors that they had heard some gigantic, mysterious roar at the same instant, that confirmed that there really had been a tornado at all.
That wreckage, of course, is another reason the tornado can take such a hold on the imagination: tornadoes are so fantastically destructive. Before tornadoes were routinely captured on video, the main visual documentation of their existence was of their aftermath. Some of the earliest photographs and newsreels of the American Midwest are scenes of tornado damage. The images, even now, are grotesque and horrifying. Schools and churches become skeletal apparitions; heavy Victorian furniture is dangling from trees; a potbellied stove sits in a pig wallow; a town has become a plateau of splintered timber. They seem almost like examples of old American tall-tale art—the surreal postcards once sold as novelties, where solemn men in bowler hats inspected impossibly vast pumpkins and strawberries: comic boasts about the strangeness of life in the American heartland.
But the deepest mystery of the tornado is its actual physical presence. This is something that even now no video image can capture. A tornado funnel has an unforgettable quality of the surreal, or the hyper-real: its unimaginable size (tens of thousands of feet high), its apparent solidity, and its terrifyingly rapid movement all make it appear like a religious vision. A tornado seems to be not a cloud but some sort of inconceivable created structure—one that reaches up from the ground to the heavens as though extending from this world to the next. You can’t help but see it as essentially supernatural.
The man who wrote “Ghost Riders in the Sky,” Stan Jones, said it was based on an old cowboy legend. He’d heard it in his boyhood from an elderly cowhand, and he had no idea how much further it went back. The truth is that it can be taken back quite a long way: to medieval Europe and to the legend of the Wild Hunt. This was another story about strange huntsmen eternally riding after supernatural prey. In various versions of the legend, the huntsmen were demons, or ghosts, or fairies; they were led by Odin or Satan or King Arthur (or all three); they were hunting a supernatural horse, or a wild boar, or wood nymphs who took the form of windblown leaves. The sight of the Wild Hunt was often taken as a presage of disaster, of a coming war or a plague; almost always it meant doom for the eyewitness, who would be stolen away in sleep to join in the hunt himself.
The modern-day equivalent of the Wild Hunt can be seen on the highways of the American heartland every spring. They are caravans of station wagons and vans and SUVs, taking atmospheric soundings with their latest meteorological software, tracking dry lines and vortex signatures, searching for the mysterious and elusive terror of the funnel cloud. It seems like the latest and most cutting-edge kind of entertainment, but it, too, is a hunt that’s been going on for a very long time. The contemporary tornado chasers are only the latest in a centuries-deep tradition of obsessive hunting. People rode after funnel clouds on horseback; they traced out damage tracks on foot, through unmapped forests and limitless swamps; they spent years sifting through paper archives, looking for the eyewitness testimony that would bring them closer to the unimaginable reality of the storm.
Most of those early hunters are forgotten now, but they used to be celebrities. James Espy, whose pursuit of the secrets of the tornado led him to be called the Storm King, was at one point the best-known scientist in America; his debates with other scientists were followed by newspapers as though they were boxing matches. John Park Finley traveled the country in the late nineteenth century to lecture on the unsuspected dangers of tornadoes and stirred up so much controversy that his career ended in a highly public shipwreck. And there were many others—professional meteorologists and obsessive amateurs, even a Founding Father, people who risked their lives, wrecked their careers, and lost lifelong friends in poisonous feuds, all for the sake of that ever-receding quarry.
Their stories are mostly buried and have to be rooted out from all kinds of obscure sources: military field reports, privately printed pamphlets, family documents, unpublished memoirs, letters to editors, newspaper interviews, transcripts of courts-martial, congressional testimonies. But from them a strange kind of history does emerge—not a succession of blandly uplifting technological triumphs, but something more ambiguous: a story of doubts and blind guesses, grinding stupidity and unaccountable insight, horrifying violence and mysterious beauty. It’s just what you’d expect from a hunt that’s still thundering onward across those endless skies.