Another season is drawing to a close. The date is June 24, 2003, and a storm-killing high-pressure ridge will soon smother the plains with hot and bone-dry weather. The tornadic activity is shifting north, into Canada.
Added to nature’s own encroaching deadline are the financial considerations. This year, he was able to get the National Geographic Society to underwrite his campaign to field the turtles, but without strong results there likely won’t be a second grant. This is the last day National Geographic Magazine’s embedded photographer, Carsten Peter, can remain on the road with Tim. Peter has already begged his editor for two extensions; the clock has run out.
The small team finalizes the day’s target, and at around eleven that morning, they step outside into a warm, gusting wind out of the south. Slate-bellied clouds give the sunlight straining through a dingy cast. Tim and Porter climb into the minivan and head north; the photographer and his guides, Gene and Karen Rhoden, a husband-and-wife storm-chasing team, follow behind in an SUV. They plot a course for the Nebraska–South Dakota border, picking their way along a tangle of state roads and federal highways through the gently undulating, grassy dunes of the Sandhills. That afternoon, they are treated to their own private air show: a pair of dogfighting jets from Offutt Air Force Base dive and bank and launch flares that streak across an acetylene-blue sky.
Tim doesn’t say much on the drive. As he steers for South Dakota, he begins to second-guess himself. Rhoden and the others had pressed for a play on the northern system of storms, which are likely to form somewhere near the border. Tim agreed, but he knows it risks missing an epic tornado farther south, in central Nebraska, Kansas, or Oklahoma. He’s been burned this way before. Normally he wouldn’t beat himself up—or even give doubt room to creep in. But Carsten Peter has just canceled yet another flight home to stay on, and NatGeo has invested thousands of dollars in his mission. They’re expecting . . . something. Tim knows his dream intercept is possible. Getting it is simply a matter of finding the right storm. On this day, though, the sheer size of the plains seems especially daunting.
A few miles after crossing the Missouri River into South Dakota, they gas up and prepare for the chase. The Storm Prediction Center in Norman, Oklahoma, has issued a tornado watch. Portions of Iowa, Minnesota, Nebraska, and South Dakota are under the gun. Particularly around southeastern South Dakota, the weather service describes the atmospheric instability as on the “extreme” end of the scale. It looks like the Rhodens were right—and, moreover, like there’s serious potential today. Once the sun begins to sink toward the horizon, an eighty-mile-per-hour jet stream will kick in from the west, and the storms will quickly intensify from severe to tornadic.
The harbingers are all around them as they head north: cumulus towers form, white as bleached cotton and smooth as polished marble; they loom like precipitous atolls over a cerulean sea. This means that warm, moisture-suffused air—TNT as far as the chasers are concerned—is convecting toward the upper-level winds that will transform gentle giants into glowering supercells.
By six that evening, thunderheads congeal into a line stretching from western Minnesota across the southeastern corner of South Dakota, and into Nebraska. As projected, they grow explosively in this charged environment, erupting into the lower atmosphere like a caldera’s rising ash column. Within twenty minutes, the first tornado touches down.
At 6:16, Tim starts tracking a northeast-bound twister near Woonsocket, South Dakota, a former rail junction in the melon and wheat country east of the James River. They’ll need to drive fast to get ahead of it, but this is a storm that could redeem the season. Roughly a mile out, they behold the prototypical vortex: its funnel is gracefully tapered, its hue ever changing with the angle of the light. When Porter zooms in on the tornado at ground level, the camera reveals staggering violence. Scarcely detectable suction vortices lick out of the earth like tongues of fire and vanish almost as soon as the eye can register what it sees. With the sun behind the plume, the particulate looks as black as coal dust. Judging by the way this tornado chews through windbreak trees like a wood chipper, it is deadly, by its nature unpredictable—an exceedingly nasty specimen for the turtles if they can get ahead of it.
Tim approaches from the east, then swings north onto a dirt road, racing parallel on a path he hopes will eventually bring them into intersection.
“Okay,” he says, “let’s get ready.”
He guns the minivan over the narrow South Dakotan back road, which is wide enough to admit only one vehicle comfortably. His eyes dart between the terrain ahead and the slender column scoriating the crops. In the camera frame is Tim’s recognizable hawk-nosed profile. The tornado is just off to their northwest, but Tim is gaining on it. In another moment they’re dead even. “I gotta wait until I get the right angle on it,” he says. The tornado continues to move steadily to the northeast. He just needs to guess where it will cross.
“Help me with some roads,” Tim instructs. Most likely, he wants to be certain that the road doesn’t dead-end ahead, as these farm lanes occasionally do.
Porter consults the computer monitor displaying the DeLorme road map. “You’ve got
