Science | September 6, 2021 12:01 pm

Experts Confirm Roundabouts Can’t Give Rise to Tornadoes

No, traffic circles don't cause extreme weather

Traffic circle
Call it a traffic circle or call it a roundabout; it still won't make a tornado.
Ádám Berkecz/Unsplash

Depending on where you came of age, you might call it a traffic circle or you might call it a roundabout. Either way, the principle is the same: cars drive around in a circle and exit at appropriate points to continue on their way. You can find them in London and New York City; you can also see them on suburban and rural highways. They’re ubiquitous. And with extreme weather on people’s minds once again, a question might come to mind — namely, could driving around one really fast cause a tornado to form?

In 2019, a Pennsylvania man called in to a local news show to make his opinion on the subject known. His opinion? That traffic circles led to tornadoes. “When people go round and round in circles, it caused disturbance in the atmosphere, and causes tornadoes,” he said.

At the time, this theory was widely disbelieved, for obvious reasons. But in the wake of Ida and Henri, it’s apparently gotten something of a second wind — no pun intended. And so Jalopnik’s Jason Torchinsky sought out an expert to debunk this theory once and for all.

Torchinsky spoke with Dennis Mersereau, author of The Extreme Weather Survival Manual, to get his insights on the matter. “Cars would never be able to start a tornado,” Mersereau told him. “Tornadoes start with rotation up in a thunderstorm and stretch down toward the ground.”

Roundabouts might be confusing for drivers, but they’re highly unlikely to spawn extreme weather in their wake. That’s one thing to reassure you in these troubling times.