What Would Happen If . . .

You Were Struck by Lightning?

ON APRIL 2, 1978, a Vela spy satellite designed to spot the telltale double flash of a nuclear bomb picked up a hit. Somebody, it seemed, had dropped a nuclear bomb on the small mining community of Bell Island off the Newfoundland coast. That seemed unlikely to military analysts—Newfoundland was an unexpected place for the Cold War to turn hot—and, indeed, a few quick phone calls confirmed that the mining community was not a nuclear wasteland.

So what had happened?

The Vela satellites ignored lightning because the flash from a nuclear bomb is far brighter. What the Velas didn’t account for were superbolts—the rare lightning strikes so powerful they mimic nuclear blasts. The Bell Island strike was a superbolt. Heard more than 30 miles away, it left a 3-foot crater, damaged houses, and exploded TV sets.

What is a superbolt? Normal lightning strikes from the bottom of a cloud, just 3,000 feet above the ground. A one-in-a-million superbolt strikes from the top—30,000 feet above Earth—and because it requires far more voltage to travel the greater distance, a superbolt is more than 100 times as powerful as regular lightning.*

Superbolts are extremely rare and most occur over water, so only a few firsthand accounts exist: On April 2, 1959, a strike in Leland, Illinois, left a 12-foot hole in a cornfield, and in 1838 a superbolt struck the 800-pound mast of the HMS Rodney and “instantly converted it to shavings,” according to Frank Lane in The Elements Rage.

So what would happen if you were really, really unlucky and stood underneath a particularly ominous-looking thundercloud that started generating electricity at its top, 30,000 feet above the ground? Would you be converted to shavings?

Probably. But the exact answer depends on exactly how the bolt strikes you and how much energy it delivers. Even a normal bolt of lightning could turn you into the mast of the HMS Rodney if the entire arm-wide bolt passed through you. They usually don’t, though, even in direct hits, because lightning ordinarily strikes victims with only a portion of its force. Some people have even survived direct strikes when the bolt “encased them” instead of passing directly through their bodies.

Becoming encased in lightning sounds like a fatal experience, but if you’re going to be hit, it’s your best chance at survival—and it helps if you’re wet. Electricity always travels along the path of least resistance, so if the bolt hits you and you’re really wet, that path might be along the outside of your skin and not through you. The strike will also charge the air immediately around you, and for an instant can turn that air into an easier path than the one through your gut.* This is called the flashover phenomenon, and some people who have been struck and knocked unconscious woke up naked after the water on their skin was instantly vaporized and blew the clothing off their bodies.

One of the biggest differences between a lightning strike and a typical household electrocution is how quickly the lightning passes through you—typically between eight to ten microseconds. In regular, run-of-the-mill, fork-in-a-socket electrocutions, the timing of the electrocution and your heartbeat isn’t as critical because the electric flow lasts a long time. In lightning strikes, exactly when the lightning passes through your heart can save you or kill you. If you’re unlucky, it would hit your heart a moment before it contracts. If the current passes through your heart during this instant—which lasts only one tenth of a second—it would likely send your heart into fibrillation, which, without a defibrillator, is certain death.

But even if you were lucky and the lightning came a moment after contraction, you would still be in danger. A superbolt can scramble an entire town’s wiring, like it did to the houses on Bell Island. Imagine what it could do to yours. Your brain works on tenth-of-a-volt signals. A lightning strike can overstimulate your central nervous system, temporarily overwhelm your brain, send you into unconsciousness, and possibly scramble your brain stem, which is the area that reminds you to breathe. If it’s sufficiently scrambled, you would forget to do that.* This can happen even if you’re not directly hit.

How can you avoid all this unpleasantness? Standing underneath a tree in a storm is a particularly bad idea.* Lightning can hit the tree, travel to the ground, and turn the area around it into a hot plate of electricity. That’s bad for you because you’re mostly just salty water, and since salt water has a lower resistance than the water on the ground you would become the path of least resistance.

The bolt would travel up one leg and down the other, hijacking your electrical system and causing your leg muscles to fire, forcing you to leap into the air. The current would also puncture and destroy the walls of the cells it passed through in a process called electroporation that would create a highway of dead material perfect for the growth of infections. The upside? At least the current won’t pass through your brain stem, so you would have a shot at remembering to breathe.

When the superbolt hit the mast of the HMS Rodney it flash-boiled every last bit of water in the mast, rapidly expanding the water molecules into gas and exploding the mast into the sea “as if the carpenters had swept their shavings overboard,” according to Lane.

If you took a direct shot from a superbolt, most of the electricity would, in all likelihood, pass alongside you. However, superbolts are powerful enough that even if most of the bolt passed alongside you, there would still be plenty left over to stop your heart and scramble your brain. In other words, you would be dead—you just wouldn’t have exploded.

But if you’re really unlucky—or let’s say you make the ill-advised decision to hold a metal rod high above you—and you take the full, dinner-plate-size bolt to the head, you would end up like the mast of the HMS Rodney. The electricity would travel down your juicy veins and organs, heat you with more energy than if you were standing on the surface of the sun, turn your water to steam, and explode you into tiny bits.*

Vela satellites would pick up the strike, and perhaps a few scientists would fly in to make sure no one set off a nuclear bomb, but all they would discover would be a few broken TV sets, a couple of rattled neighbors, and one evenly distributed human.