When thunder rumbles several afternoons in a row, as it’s been doing this month, one might be tempted to ignore it and continue with outdoor activities. Young people, including my sons in their 20s, often underestimate the closeness and hazards of lightning.
The government website ready.ga.gov ranks lightning as the No. 2 cause of Georgia weather-related deaths, after tornadoes. But if you include car crashes in bad weather, those could easily take first place.
When thunder is audible, lightning is already occurring nearby. The explosion of air in a lightning bolt is causing the noise. Sound travels slowly, taking five seconds to cover 1 mile. Beyond a dozen miles, thunder is rarely audible. Once you hear it, the storm is close enough to strike in the immediate vicinity. The refrigerator magnet saying “When thunder roars, go indoors!” from noaa.gov is as valid as ever.
A house offers sufficient protection from lightning to its occupants, but not to delicate electronics. It’s wise to unplug computers, stereos and TVs from the wall during a lightning storm. “Surge protector” type power strips may shield equipment from electrical spikes that occur when there’s trouble in the circuits unrelated to severe storms.
But if lightning strikes the main power line, the current can jump the protective diodes in the unit and kill the equipment behind it. Even uninterruptible power supplies, which do such a nice job during “routine” surges and outages, don’t prevent electronics from being destroyed.
I learned that $1,300 lesson when lightning struck the Brenau campus a few summers ago. Even with the computer’s power cable unplugged, the surge found an ethernet line and killed the motherboard, central processor chip and network card.
Mobile equipment like laptops or smartphones are best unplugged from their chargers. There, too, the current can overwhelm the circuitry and cause destruction. The same is true for phone lines.
It’s not necessary to sit in a dark house during the storm. Having the lights on doesn’t “attract” lightning. Nor does a car. It’s not a good idea to go joyriding in a storm, due to the accident hazard on slick roads and with poor visibility.
But a metal-roofed vehicle makes lightning run off on the outside without harming passengers. This isn’t true for convertibles, tractors and motorcycles. Contrary to old legend, rubber tires don’t protect against getting struck by lightning.
Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays and at gainesvilletimes.com.