Trillions of periodical cicadas are emerging throughout states in the U.S. after nesting underground for a over a decade.
Two huge broods of cicadas are beginning to come above ground throughout the country in a rare double emergence not seen and heard for more than 200 years. Twelve U.S. states are expected to be affected, with a handful of states already reporting the characteristic loud buzzing sound and swarms of the insects flying around.
Periodical cicada broods develop below ground over several years before emerging when the soil hits 64 degrees Fahrenheit. They are then active for around a month above ground as they reproduce and lay eggs before dying off. Approximately the size of a paperclip, periodical cicadas are unique to North America, and come up from the ground around every 13 to 17 years, depending on a brood's specific cycle.
"If we accept an estimate of a million cicadas per acre and if the total combined area of a periodical cicada emergence is roughly the size of Delaware, then more than a trillion cicadas will be involved," according to researchers at the University of Connecticut. "Trillions of adult cicadas will be present—but not all in the same place at the same time."
While cicadas are a vital part of the ecosystem and pose no threat to humans and animals, the loud buzzing sound they make can still be quite irritating. And this could be heard by millions of Americans as this spring the extremely rare double emergence gets underway.
Where Are Cicadas Expected?
This year, two broods are expected to emerge: Brood XIX, also known as the Great Southern Brood, will come aboveground in the southeastern states of Alabama, Arkansas, Georgia, Kentucky, Missouri, Mississippi, North Carolina, South Carolina, Tennessee and Virginia.
Brood XIII, also known as the Northern Illinois Brood, will be seen in the Midwest, primarily in Illinois and Iowa. The double emergence of this kind is the first recorded since 1803—221 years ago, when Thomas Jefferson was in the White House.
Where Have Cicadas Emerged?
While a definitive list of where cicadas swarms have been identified above ground is not available, local news websites have reported several instances.
According to Georgia-based local news site 11 Alive, numerous counties reported cicada swarms throughout late April. In North Carolina, the cicadas are causing such a nuisance that residents have called 911 due to the incessant noise sounding like alarms.
"As cicadas emerge, some have likened the sound to an alarm. ... Please refrain from dialing 911 if you believe the noise you are hearing is cicadas," Union County authorities told residents, according to a report by Queen City News.
Similar reports have been made in neighboring South Carolina. Newberry County sheriff Lee Foster described the brood's emergence as "biblical," to NBC News, but warned local residents there was no need to raise the alarm with authorities.
According to a report by NBC Chicago, cicadas are emerging earlier than expected in Illinois.
"The periodical cicadas have been emerging for the last week and a half," according to Stephanie Adams, plant pathologist at Morton Arboretum in Lisle, DuPage County. "We found them both out here in our landscape and also in our east woods."
Have you been affected by the cicada swarms? Do you have images or videos to share? Email a.higham@newsweek.com.
Uncommon Knowledge
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Aliss Higham is a Newsweek reporter based in Glasgow, Scotland. Her focus is reporting on issues across the U.S., including ... Read more
