Ever Seen A Wave In The Sky?

Sign up for the Morning Brief email newsletter to get weekday updates from The Weather Channel and our meteorologists.

They look like breaking waves from the ocean evenly spaced across the sky, but you're looking at clouds in the video above.

The photo seen below, taken from the summit of Mount Major in New Hampshire, distinctly shows the impressive Kelvin-Helmholtz clouds at sunrise.

Weather in your inbox

Forecast Location

Sign Up

By signing up you agree to the Terms & Privacy Policy. Unsubscribe at any time.

Kelvin-Helmholtz clouds, which can also be referred to as fluctus clouds or billows, form when air is moving at two different speeds.

"They form in an environment of strong wind shear," said weather.com senior meteorologist Jon Erdman. "Winds at the top of the cloud are moving faster than at the cloud's base. That causes the top to lean over and crash downward like a breaking wave."

While the clouds are rare, they are usually found on windy days and are a good indicator that nearby aircraft are experiencing turbulence.

"What makes Kelvin-Helmholtz clouds so cool is they're a reminder of how the atmosphere is a fluid, like water," said Erdman. "Similar to breaking waves at the beach, Kelvin-Helmholtz clouds are breaking waves in the atmosphere."

(For even more granular weather data tracking in your area, view your 15-minute details forecast in our Premium Pro experience.)