In the spring of 1997, Tim receives an unexpected phone call. As it rings, he has no idea that this conversation could change the course of his life, or that he sits amid a vast sea of forces just one nudge away from alignment. He’d never be able to know it at the time—but the click, as he picks up his phone, is the shift that sparks the storm.
The man on the other end of the line is a mechanical engineer from Huntsville, Alabama, named Frank Tatom. He runs his own firm specializing in the dynamics of turbulent flow and explosive damage, and he has found Tim’s name in a search for tornado chasers across the Midwest. He has a proposal that he thinks Tim will want to hear.
Eight years ago, Tatom begins, a violent twister entered the southern sector of Huntsville before the sirens could sound. Nobody saw it coming. The tornado cut across highways choked with rush-hour traffic, killing eleven people. Another eight died in their homes and businesses. Two other victims held on for a while before succumbing to their injuries in the hospital. Huntsville looked like a war zone. The damage path was a half mile at its widest, and nearly nineteen miles long.
Tatom had been reeling just like everyone else, but amid all the heartbreak and pain, one story struck an odd note to his engineer’s ear, if only for its inexplicability. A man working at a service station told Tatom that minutes before the tornado arrived, he had the hood up on a woman’s car. Suddenly, the ground beneath his feet began to tremble. Even the motor in front of him seemed to vibrate like a tuning fork. He didn’t know what was coming, but he grabbed the woman and pulled her into the service station. “The man took her to his office, threw her down near the counter, and jumped on top of her,” Tatom relates to Tim. Then, they heard the roar, faint at first but soon deafening. The building took a direct hit, and the two were flung into the street, rattled but miraculously alive.
The story made Tatom’s hair stand on end, and the more he looked around, the more he discovered the man’s experience wasn’t unique. The choir leader at Trinity Methodist felt the vibrations through his feet as he sheltered in the church basement. Both a police officer and the city’s emergency manager reported the same sensations. Tatom went to the nearest US Geological Survey office. The geologists there confirmed a low-frequency seismic signature—a series of apparent shock waves that accompanied the storm.
In the years following the tornado, Tatom couldn’t stop thinking about the vibrations on that terrible day. Could the wind really have caused the earth to tremble? He and an expert in soil dynamics and seismic signals at the University of Alabama decided to chase down the hypothesis. With their combined expertise, in 1993, Tatom and Dr. Stanley Vitton concluded that the tales of tremors weren’t at all far-fetched. In fact, they surmised, the most violent tornadoes transferred a jaw-dropping amount of force into the earth—the energy equivalent of half a ton of TNT per second.
Tatom’s bold idea finally clicked into place: What if seismic sensors could have warned Huntsville back in 1989?
Tatom has since devised a prototype instrument package he calls the snail. Its components are quite simple: an aluminum basin from Walmart houses a battery, and a recorder microprocessor that’s connected by cable to a geophone—a sensor used to detect seismic signals with three sensitive transducer prongs plunged into the ground. Theoretically, the device should be able to detect tornadoes at a distance of twenty-five miles. The idea is to position snails at intervals around the city as a kind of early-warning network.
By the time he calls up Tim, NOAA and the Department of Commerce have already awarded Tatom a Small Business Innovation Research grant to take the snails to Phase I: production and testing. He now needs to prove his concept by deploying the snail near a violent tornado. This is where Tim comes in. Tatom is just an engineer, he explains—a man of equations and microprocessors and laboratories. He knows nothing whatsoever about hunting twisters. But Tim’s prowess as a chaser precedes him.
Can you get my invention close to a tornado? Tatom asks. Can you help me find out if it actually works?
What he’s proposing sounds a great deal like the NOVA documentary Tim saw years ago, in which scientists lugged their high-tech TOTO probe across the plains in pursuit of scientific knowledge. It’s the very notion that started Tim chasing.
Send the snail, Tim replies.
Before the spring storm season arrives, a single snail—number five in the fleet—is delivered to his doorstep in Lakewood. Examining the instrument, fashioned out of household fixtures and seismic sensors, Tim may as well be looking into his future. If the phone call was the spark, this glorified sink basin is the first rising thunderhead. He practices deploying the snail and its geophones in his yard, closely watching the weather patterns for the shape of the year’s first tornado. He won’t wait long.
Tim and his brother-in-law, Pat Porter, gear up to hit the plains on Memorial Day weekend. Tim is more excited than he has ever been about a chase; this one will be unlike any he has ever embarked on. Gathering footage and sending ham radio updates to SKYWARN have never required proximity. Deploying the snail, however, will mean heaving aside nearly every piece of chaser wisdom he’s ever absorbed. What happens to the first and only rule—don’t get too close—when close is exactly what Tatom needs?
Tim has never considered himself a daredevil. He has always avoided entering the rain and hail core that directly surround the funnel. He stays out of the tornado’s way. But if he is to succeed now, he may well have to deliberately enter the path. Tim has enjoyed storms for roughly a decade now,
