In 1925 a tornado ripped through Griffin, Indiana, midway through a 219-mile-long killing spree. There’s some question today whether the tornado was a single twister or a series of them, but 689 people died that day and thousands more were injured–so if it was one tornado it was certainly the worst ever recorded in U.S. history.

Forty years later I moved with my family into one of the three houses in Griffin that had been left standing after the big storm. Everybody in town had a horror story to tell about the 1925 cyclone, and I obsessed over every fragment of information. The twister had struck in the afternoon. Children were killed when a school bus overturned on its way home. Mrs. Wilson’s baby was lifted right out of her arms, never to be seen again. Mrs. Majors fell into a long coma when the wind drove her hairpins into her brain. Altogether, in a town with 150 homes and a population of 400, 147 houses were destroyed and 60 people died.

With tornado watches and warnings flashing onto the television regularly every spring and summer, my parents established that the safest spot in the house to wait it out was underneath the staircase in a triangular space where the camping gear was stored. Sometimes I snuck into it for practice, carrying a flashlight and crackers and carving out a nest for myself among the sleeping bags.

All of this did an incredible job of feeding my nightmare-making machinery, and to this day I’ve never shaken free of tornado-infested nights. I’ve had dreams where I was picked up and tossed about, ones where I spotted the funnel cloud coming toward me and outran it, ones where it passed over me as I hid in a culvert, and ones of which I was the sole survivor.

The other day I talked with Stu Ostrow, a meteorologist with the Weather Channel who’d just come back from chasing tornadoes across the Great Plains. The Weather Channel is producing a documentary, not on tornadoes but–in a rather self-referential move–on the people who track them. It turns out there’s a whole subculture of people who drop what they’re doing whenever there’s a great storm brewing and drive or fly to it in the hope of seeing a funnel cloud drop to earth. Some are scientists, some hope to sell video or photos to the media, and some are just tornado junkies. “There’s a fine line between being in the right place at the right time and being in the wrong place at the wrong time,” Stu admitted.

The Weather Channel team caught up with its first tornado in the Texas panhandle. It was 12 to 15 miles away, but the crew had a clear, dramatic view. The second one was closer but shortlived–the best part about it was the enormous chunks of hail that fell. The third one they encountered was only two to four miles away, which turned out to be too close for observation and comfort. The group ended up in a van during the worst of the thunderstorm, nervous because the rain was obscuring the tornado and they might soon be in its path. But in the end they escaped safely.

Tornadoes can occur any month of the year anywhere in the world, though midwestern America is the perfect laboratory for brewing up a vortex. When warm moist air glides up from the Gulf of Mexico and cold air sails in from Canada, the two collide over the flattened plains and the hot air struggles to rise, creating a violent convergence that results in a thunderstorm and sometimes in a tornado. Yet when I moved to Chicago I gradually replaced my fear of tornadoes with a fear of human violence. Forces of nature no longer seem threatening to me–the urban illusion of insulation from nature gives me a sense of security. Getting caught in the cross fire of a drive-by shooting? Sure, that seems possible. Getting mowed under by a twister whipping down Michigan Avenue? That’s absurd.

I asked Stu if I had any justification for this sense of security. Was there anything about the geography of Chicago that would help insulate it from tornado attack? Something about the presence of the lake, maybe, or the density and height of the buildings that might prevent a tornado from forming?

“I wouldn’t bank on it.” Though it’s possible, Stu conceded, that Lake Michigan’s cooling effect might have a calming influence on the atmosphere that would deter the formation of tornadoes. Some people hold to the theory that the presence of skyscrapers would break up a tornado by changing wind patterns. But in Stu’s opinion if a tornado swept up from the southwest, or even the northwest, it could keep going once it hit town. Tornadoes are perfectly capable of going up and down hillsides, which scientists once believed they didn’t do, so there’s no reason to think that tall buildings would pose an obstacle. “There haven’t been any cases of a tornado going right downtown in a big city,” Stu said. “But one of these days it’ll probably happen.”

We may feel braver in the face of nature when most of what surrounds us is made by humans, but in reality much of our urban environment would be used against us by a tornado. A 200-mile-an-hour wind tosses trucks into cottonwood trees and collapses buildings on top of innocent people, and there’s not a damn thing we can do about it.

A month ago I dreamt I was working in a rice field next to an old woman dressed in white linen, who labored diligently. I followed her lead but was uncertain of the work. Since the sky was a strange green color, I asked her about tornadoes. Silently, she pointed to a funnel cloud far off on the horizon that was reaching down from the thunderheads toward the earth. I wanted to run for cover and tried to convince her to come with me; she was elderly, and I felt I had responsibility for her. She indicated that I should stand still and watch it. Majestically, it rose and fell over the land in a slow, faraway dance.