Robert Brown|South Carolina sheriff: Stop calling about that 'noise in the air.' It's cicadas.

Do you hear that noise?Robert Brown Before you call the police, check outside: it might be cicadas.

That's what one South Carolina sheriff's department said as it asked residents to stop calling related to the recent cicada activity.

In a post on social media, the Newberry County Sheriff's Office in Newberry, South Carolina said it has received several calls about a noise sounding like a siren, whine or roar.

South Carolina has annual cicadas, which appear every year as the name suggests, and starting soon, the periodical Brood XIX, which emerges every 13 years in huge numbers.

"Although to some, the noise is annoying, they pose no danger to humans or pets," the the sheriff's department's post reads. "Unfortunately it is the sounds of nature."

South Carolina will likely see both annual cicadas and the 13-year Brood XIX, one of two broods emerging in over a dozen states across the Midwest and Eastern Seaboard in the coming weeks. The two broods, Broods XIX and XIII, haven't emerged at the same time since 1803, and are not predicted to do so again after this year until 2245.

How loud can cicadas get?

You'll know when the trillions of cicadas emerging soon make their entrance, as the species is famous for the amount of noise they make.

When Brood X emerged in 2021, both journalists and citizens reported noise levels ranging from 90-100 decibels, according to the Centers for Disease Control and Prevention, who also noted that cicada noise 3 feet from a heavily infested tree can approach 100 decibels.

While they are loud, the noise you hear from cicadas is unlikely to cause hearing loss. The CDC says the exposure period, duration and distance is just as important as how loud a sound is when influencing hearing loss.

For example, you can listen to a noise that is 85 decibels for 8 hours safely, 94 decibels for 1 hour safely or a noise that is 100 decibels for 15 minutes safely.

2024 double cicada broods: Check out where Broods XIII, XIX will emerge

The two cicada broods will emerge in a combined 17 states across the Southeast and Midwest, with an overlap in parts of Illinois and Iowa. They will emerge once soil eight inches underground reaches 64 degrees, expected to begin in many states in mid-May and lasting through late June.

The two broods last emerged together in 1803, when Thomas Jefferson was president.

Where is Brood XIX in South Carolina?

Brood XIX will only be found in a few Upstate South Carolina counties, and are expected to emerge in the state once conditions are right, mid-April to mid-May.

The cicadas will likely be seen in natural areas, including protected areas and parks, Eric Benson, Clemson University's extension entomologist, told the Greenville News, part of the USA TODAY Network.

"In South Carolina, the data shows that (we will see the cicadas) pretty much from Columbia up through the Upstate and into the mountains," Benson said.