Listen: US hit by “cicada-geddon” as broods emerge from underground in rare double event

John Cooley, a University of Connecticut cicada expert, has dubbed the phenomenon “cicada-geddon”. “Periodical cicadas don’t do subtle,” he previously said.

Mr Cooley uses hearing protection because the sound from the creatures can get so intense.

“It’s up in the 110 decibel range,” Mr Cooley said. “It’d be like putting your head next to a jet. It is painful.”

Periodical cicadas are found only in the eastern US and a few other places. There are 15 different broods that hide away and come out every few years, on 17- and 13-year cycles.

The largest geographic brood in the US is called Brood XIX and comes out every 13 years in the south-east when the ground warms to 17.8C. The bugs are brown at first but darken as they mature.

Meanwhile, Brood XIII comes out every 17 years in Illinois.

The last time these two broods came out together was in 1803. Thomas Jefferson wrote about cicadas in his Garden Book but mistakenly called them locusts.