Emerging cicadas are so loud in one South Carolina county that residents are calling the sheriff's office asking why they can hear a "noise in the air that sounds like a siren, or a whine, or a roar."

The Newberry County Sheriff's Office posted a message on Facebook on Tuesday letting people know that the whining sound is just the male cicadas singing to attract mates after more than a decade of being dormant.

Some people have even flagged down deputies to ask what the noise is all about, Newberry County Sheriff Lee Foster said.

The nosiest cicadas were moving around the county of about 38,000 people, about 40 miles northwest of Columbia, prompting calls from different locations as Tuesday wore on, Foster said.

Their collective songs can be as loud as jet engines and scientists who study them often wear earmuffs to protect their hearing.

After Tuesday, Foster understands why.

"Although to some, the noise is annoying, they pose no danger to humans or pets," Foster wrote in his statement to county residents. "Unfortunately, it is the sounds of nature."

Cicadas are already emerging in southern states, like South Carolina, where it warms up faster, while in cooler states, such as those in the upper Midwest, they might not emerge until June. 

This year, two broods of cicadas are emerging: Brood XIX, which comes out every 13 years, will emerge in Georgia and the Southeast, and Brood XIII, which emerges every 17 years, will appear in Illinois. 

This will be the first time since 1803 that two broods emerged simultaneously. The next time this happens will be 2037. With this convergence, the bugs will arrive in numbers that have not been seen in generations. 

The dual cicada brood emergence will primarily be seen in parts of Illinois and Iowa, as well as parts of Kentucky, Missouri, Arkansas, Tennessee, Mississippi, Alabama, Georgia, South Carolina, North Carolina and Virginia. 

Cailtin O'Kane contributed to this report.

In:
• Cicadas
• South Carolina
• Environment