In what experts are calling a "cicada-geddon," trillions of cicadas are preparing to emerge in what could be the largest bug emergence in centuries. This double dose of weirdness will see two separate groups of cicadas resurfacing after long periods underground.

The first group, known as Brood XIX, is set to emerge around mid-May. Considered the largest periodical cicada group, they make their appearance every 13 years. Dr. Frank A. Hale, from the University of Tennessee's Extension program, estimated that certain areas may see an astonishing number of up to a million cicadas per acre.

As Brood XIX fades away, another group, Brood XIII, will take its place. This group emerges every 17 years, and the last time Broods XIX and XIII co-emerged was in 1803. The upcoming emergence, however, will mark the first time in recent years that a 13-year brood and a 17-year brood will appear together.

Brood XIX, also known as the Great Southern Brood, is expected to emerge across numerous states, including Alabama, Arkansas, Georgia, Illinois, Indiana, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, and Virginia. On the other hand, Brood XIII will have a more limited range, appearing only in Indiana, Illinois, Iowa, Wisconsin, and potentially Michigan. However, even those living outside these areas may still encounter stray cicadas.

For those living in the Western states, such as Utah and California, there is likely no need to worry about an onslaught of cicadas. The U.S. Department of Agriculture Forest Service has noted that cicada broods are primarily concentrated in states along or east of the Mississippi River.

Both Brood XIX and Brood XIII are expected to emerge simultaneously in mid-May, as temperatures rise and the ground becomes warmer. Experts believe that these cicada swarms could reach astronomical numbers, with estimates ranging from hundreds of trillions to possibly quadrillions of cicadas in total.

It is important to note that while these cicadas can be loud and may occasionally urinate on unsuspecting individuals, they pose no harm to humans or pets. Their presence is more of a spectacle, as they overwhelm areas with their sheer numbers and distinctive singing.

As the emergence of these fascinating insects draws nearer, people across the eastern U.S. can expect to witness a truly remarkable natural phenomenon. Brace yourselves for an unprecedented swarm of cicadas and get ready to experience the sights and sounds of this incredible event.