Researchers originally following the emergence of Brood VI cicadas in South Carolina and Georgia observed Brood X cicadas emerging this spring. The phenomenon was then observed in North Carolina, Virginia, Maryland, the District of Columbia, Ohio and Indiana.
Researchers continue to follow the emergence of both broods of cicadas but the earlier-than-expected appearance of Brood X is described to be related to, "warming climate, with more warm weeks a year during which the underground nymphs can grow" which, "could be triggering some cicadas to emerge ahead of their brood". Read the Scientific American article to learn more.