Millions of noisy cicadas to emerge on the East Coast after 17 years underground

After 17 years underground, a brood of periodical cicadas will emerge in swarms as weather warms in several East Coast states. Their unmistakable shrill will serve as the soundtrack to the summer, peaking in June.

Up to 1.5 million cicadas per acre are expected to emerge in parts of Virginia, West Virginia, and North Carolina, reports ScienceAlert. This year marks brood IX's first emergence since 2003.

The mysterious bug only lives 4 to 6 weeks, and their aggressive noise — a mating call — can reach 90 decibels, as loud as a lawnmower. Scientists haven't quite cracked the code to periodical cicada's life cycle, but hypothesize they have evolved to avoid syncing up with the life cycle of predators.

In addition to the racket, cicadas can pose a threat to trees. Females lay their eggs in branches, which may cause them to split. If a tree is populated with enough eggs, it could die, per ScienceAlert.

It's not all bad news, though. Cicadas are harmless to humans and pets, and they naturally "turn over soil and prune trees, increasing flowers and fruits in later years," ScienceAlert reports.

If you're feeling left out, have no fear. Cicadamania reports next spring, brood X is set to emerge in Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Washington D.C.