The Straight Dope

What’s the deal with not taking a shower, using the phone, or standing too close to the TV during a thunderstorm? If people were electrocuted by lightning in their homes on anything like a regular basis surely we would hear about it more often than we do. Is this just one of those stories our parents tell us over the years so now I can terrify my own son? –Jim L., Windsor, New York

A skeptic, are we? You probably thought those warnings about waiting an hour after eating before swimming were silly, too. Well, they were. Lightning, unfortunately, is a different story. A few cautionary tales from the medical journals:

In an incident reported in 1985, two Danish women, neighbors living several hundred meters apart, were talking on the phone during a thunderstorm when lightning struck an electric wire, shorted across to an underground telephone cable, and blasted through their handsets. Both were thrown to the floor, each with an eardrum ruptured due to the extremely loud noise, estimated to be at least 155 decibels. In addition, both had star-shaped burns on their necks and shoulders, presumably where the juice had entered their bodies. The women recovered their hearing after surgery.

An Australian man was talking on the phone while sitting on a kitchen stool with his right leg touching the dishwasher. Lightning struck the phone line somewhere upstream, traveled through the line, fried the phone, and slammed the guy into a wall. He was knocked out for a few seconds and for a minute couldn’t breathe or speak. Branching red, fernlike marks on his skin, known as Lichtenberg figures–the traces of the skittering current–extended down his neck, across his torso, and down his right thigh to the point where what was left of the bolt entered the dishwasher. His body hair was singed and his right leg was paralyzed. He recovered fairly quickly but three months later still had mild hearing loss.

In 1962 a Danish man was on the phone when lightning struck nearby. He heard a sharp crack and was partially deafened. Nineteen years later he was completely deaf in one ear and dizzy besides. A scan of his head showed a large calcified noncancerous tumor inside his skull near his ear, presumably the result of bleeding following trauma to the inner ear.

Lightning causes way less damage to houses and the people in them than it used to because most buildings and utilities now are well grounded. Research by Ron Holle, a meteorologist formerly with the National Severe Storms Laboratory, suggests that out of a typical 75 U.S. lightning fatalities per year, one person on average is killed while using the phone, another two or three die due to lightning conducted through pipes, wiring, etc, and one or two are killed by lightning-caused house fires. It’s estimated that 10 people are injured by lightning for every one killed. Considering there are 25 million cloud-to-ground lightning flashes in the U.S. annually, that’s not many. By contrast, in the early 1980s, 60 to 80 Australians were injured by lightning each year while on the phone, a rate roughly 45 times higher than the comparable rate in the U.S. At the time Australian phones weren’t connected to the house electrical ground. Now they are.

Effective as grounding is, if lightning strikes close enough, the fearsome current involved–anywhere from 10,000 to 200,000 amperes–can defeat even the most reliable protective measures. That means parental advice about staying off the phone, out of the shower, and so on during lightning storms is still worth heeding. Even a relatively small jolt can fry delicate electronic equipment. According to Holle, the U.S. insurance industry pays 300,000 claims annually for home damage due to lightning, a large fraction of which involve electronics. Cheap surge protectors don’t offer much security; if you can’t afford the $50 kind and your computer contains critical data, unplug it before (not during) an electrical storm.

There’s nothing like lightning to convince you of the fundamentally random nature of the universe. In a case reported in 2003, a man was fussing with wood in the fireplace of a Belgian farmhouse during a thunderstorm while his five-year-old daughter played at a nearby table. A glob of ball lightning–a rare, poorly understood phenomenon that behaves like a mixture of electricity and fire–emerged from the fireplace and shoved the man back three meters, burning him and knocking him unconscious. According to his wife, an eyewitness, the ball lightning then made a 90-degree turn and drifted over to the little girl, burning 30 percent of her body; glided underneath the table, through the kitchen, and into another room; and finally exited through the open back door and vanished in the garden. The scientific mind at such times does not try to think up precautionary measures. Rather it says: Yipes.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.