Trillions of periodic cicadas are soon expected to emerge from the ground as part of a rare event.

Two broods, or groups, will appear in more than a dozen states - but not Pennsylvania.

“The 17-year Brood XIII is mostly in the Midwest while the 14-year XIX brood is mostly southern,” explained Pat “Porcupine Pat” McKinney, environmental educator for the Schuylkill Conservation District.

The Brood XIX periodicals will be creating a buzz in Arkansas, Georgia, Illinois, Iowa, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina and Tennessee, and Brood XIII will be in Iowa, Illinois, Indiana, Michigan and Wisconsin.

The broods will overlap in parts of Illinois.

Their convergence, McKinney said, will create a “Swarmageddon.”

The simultaneous hatch is very rare, and something that hasn’t happened since 1803. The next double emergence of the two broods is predicted in 2245.

It’s so unusual, McKinney said, that he’s heard that Illinois tourism officials are promoting cicada tours.

“We don’t expect anything unreal here. Otherwise just our regular annual cicada mix that we get,” McKinney said. “Nothing special!”

Unless “stragglers” - or off-cycle cicadas emerge - it will be several years until Pennsylvania sees a high-density hatch.

The last emergence was in 2021, when parts of the commonwealth welcomed cicadas from Brood X, referred to as the Great Eastern Brood. On the 17-year cycle, the group will return in 2038.

And most of the Times News’ coverage area was part of the emergence of Brood II, or the East Coast Brood, in 2013. They’ll be back in 2030.

The Jim Thorpe area had an unexpected emergence of millions of periodical, straggler cicadas in 2016, which showed up around Lehigh Gorge State Park. Experts believe it was a disjunct brood related to Brood XIV.

As for the 2024 broods, they’re already being reported in Georgia, North Carolina, South Carolina, Alabama, Mississippi, Tennessee, Arkansas, Kentucky and Missouri, according to Cicada Safari.

They emerge at the end of their 17-year and 13-year life cycles when soil temperature is right - usually in May or June.

The periodical cicadas are around 2 inches long, and have black bodies and red eyes.

The males have a loud and shrill call that they use to attract mates. A chorus of the calls can be deafening.

According to published reports, folks in North Carolina recently began calling their local police department to report incessant “car alarms.” The noise, however, was from the cicadas.

While Pennsylvania won’t have periodical cicadas this year, it will have annual cicadas. The “dog day cicadas” appear each summer, typically between July and September.

The annual cicadas are also around 2 inches but have greenish-black bodies and black eyes.