(CNN) — Looking up, you might be thinking you're under a roiling, stormy sea.

But what you're looking at is a unique and breathtaking meteorological phenomenon. And today, World Meteorological Day, it's being officially recognized: asperitas cloud.

This is how the new edition of the International Cloud Atlas describes it, in almost poetic form:

"Asperitas is characterized by localized 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."

What's in a name?

Asperitas comes from the Latin word for roughness.

In 2006, the Cloud Appreciation Society , a group of weather enthusiasts based in the UK, received the first images of the distinctive cloud from Cedar Rapids, Iowa. A few years later, they proposed the cloud be included in the atlas. That would be a huge coup since the atlas is widely used to train meteorologists from the time it was first published in the late 19th century.

"When we know the name of something, we began to know it in a different way and when we began to know it, we began to care about it," Gavin Pretor-Pinney said at a World Meteorological Day ceremony in Geneva.

A big deal

Adding a new cloud type is rare. The World Meteorological Organization had not updated the atlas in 30 years, until now.

"It is a classic example of citizen science, in which observations by the general public, enabled by the technology of smartphones and the Internet, have influenced the development this most official of classification systems," a news release on the Society's website reads.