Cicadas Are Back After 17 Years!

After hanging around underground for 17 years, billions of flying bugs known as cicadas are due to sweep over the East Coast starting sometime in the next month. And although it's too early to predict exactly where or when the brood will appear, this spring's emergence should rate as the most closely watched bug-out in history.

The outbreak is expected to start in the Carolinas in April or early May, and work its way up northward to Washington, Philadelphia and New York by early June. The timing depends on the weather: Cicadas dig "escape chimneys" up from the ground where they've been maturing for the past 17 years — and when the temperature reaches 64 degrees Fahrenheit, that signals the insects to rise up, wriggle out of their shells, take wing and look for mates.

The bugs are mostly harmless to plants and humans. But the 90-decibel buzz of a sky-darkening swarm can be a bit much.

This particular group of cicadas, known as Brood II, hasn't surfaced since 1996.