This incredible time-lapse footage, filmed on an iPhone 6, shows a cloud formation known as undulatus asperatus rippling and pulsating over Augusta, Georgia, making the city look as though it's been plunged underwater. In fact, these beautiful clouds are so distinctive that they might end up being the first new cloud type to be added to the International Cloud Atlas since 1951.
The video was captured by anaesthesiologist Alan Walters, who was on shift at University Hospital in Augusta when he noticed the rippling skies outside. And because, you know, pics or it didn't happen, he decided to tape his iPhone to the window so he could document the whole thing while he gave an epidural to a patient. The footage that resulted from this totally sensible decision was later uploaded to YouTube by Natalie Waters.
So what causes these striking clouds? Researchers are still in the process of studying the precise conditions that trigger them, but although they look pretty ominous, they're not usually followed by a storm. In fact, they're most likely to form around morning or midday following thunderstorm activity.
The guy behind the campaign to officially classify undulatus aperatus is Gavin Pretor-Pinney, the founder of the US Cloud Appreciation Society. He told The Verge back in 2014 that he's sent photos of these clouds at least every six months.
"They struck me as being rather different from the normal undulates clouds," he said. "They were more turbulent, more confused - as if you were underneath the water looking up toward the surface when the sea is particularly disturbed and chaotic."
And while the World Meteorological Organisation, which governs the International Cloud Atlas, hasn't officially added the cloud type just yet, it's taken the time to propose an official definition:
"A formation made up of well-defined, wavelike structures in the underside of the cloud, more chaotic and with less horizontal organisation than undulatus. Asperatus is characterised by localised waves in the cloud base, either smooth or dappled with smaller features, sometimes descending into sharp points, as if viewing a roughened sea surface from below. Varying levels of illumination and thickness of cloud can lead to dramatic visual effects."
So it's looking pretty promising that undulatus asperatus will soon be atlas official, but regardless of classification status, we're already fans.