On June 20, 2007, thunderstorms sprung up in eastern Oklahoma. A tornado was spotted tearing the roof off a shed, damaging a few homes and pulling trees out of the ground. All in all, this was not a particularly memorable severe weather day in Oklahoma, except for one thing — one of those thunderstorms generated a 199½-mile long bolt of lightning that stretched from one side of the state to the other.
That’s a world record, says the World Meteorological Organization. And actually, it’s the first of two official world records relating to lightning. It also confirmed a lightning strike that lasted 7.74 seconds over Provence-Alpes-Côte d’Azur, France, in 2012. That strike now holds the record for the longest-duration lightning flash.
Scientists have been using ground-based lightning detection networks to monitor and measure the strength and duration of lightning strikes. Until now, meteorologists thought that strikes typically lasted no more than one second, and could travel about 20 miles from a storm. This project proves that those assumptions were not even close to reality.
John Jensenius tracks lightning deaths for the National Weather Service. Jensenius says the record “demonstrates the far-reaching effects of lightning, and just how far around a thunderstorm the atmosphere can be electrified,” he told The Washington Post. “People need to be aware that any time a thunderstorm is in the area, there is a threat of a potentially deadly lightning strike.”
Lightning deaths rapidly declined in the mid-20th century, after peaking at over 400 per year in 1943 and 1944. Since 2000, lightning deaths have been consistently below 50 per year. But that’s still too many, because we know how to prevent them.
The National Weather Service has a simple slogan for lightning safety: When thunder roars, go indoors. It sounds hokey, but it’s rooted in serious science. Once you hear thunder, it’s important to stay sheltered until at least 30 minutes after the last rumble. Just because the rain has stopped doesn’t necessarily mean you’re safe yet.
“The vast majority of lightning flashes occur within 10 miles and 30 minutes of where thunder could be heard from a previous flash,” Jensenius said. “The greatest exception is the first flash.”
“Our recommendations are likely to stay the same,” he added, even with the record for lightning distance.
Earlier this year, scientists found a new “lightning capital of the world” based on high-resolution satellite data. Lake Maracaibo in Venezuela receives an annual rate of 233 flashes per square kilometer. Before this, the Congo Basin in Africa was thought to be the most lightning-active location in the world. Still, the continent boasts six of the world’s top 10 locations for lightning strikes.
In the paper that announced the distance record, which was accepted by the Bulletin of the American Meteorological Society, it noted that these records exist because scientists could observe them. It’s possible — even likely — that lightning strikes have traveled farther and lasted longer. We just don’t know about them. They use the highest wind gust record — 253 mph in Australia — as an example. We know that tornadoes produce winds much stronger, but they have never been directly measured.