Like vinyl, celluloid and the rules of baseball, the Cloud Atlas – first published in 1896 – has seldom changed over the years.
But since the last update 30 years ago, there has been a renewed interest in clouds, mostly thanks to widespread digital photography and platforms like Flickr and Instagram sharing cloud imagery on a global scale.
Some of the rarer cloud types were seldom documented until they started appearing on social media feeds around the world. According to the World Meteorological Organization (WMO):
"The new Atlas combines 19th-century traditions with 21st-century technology. It contains hundreds of images submitted by meteorologists, photographers and cloud lovers from around the globe."
Now let's review the more spectacular additions to the Atlas:
Derived from the Latin word for 'rough,' the asperitas cloud was only identified because 'citizen scientists' began documenting weird, undulating shapes in the skies and reporting it to the WMO. With enough data, meteorologists were able to identify a pattern and classification.
Also known as a 'roll cloud,' the frightful, tubular monolith has the appearance of a giant steamroller in the sky. It is one of the few new clouds that constitutes a species of its own.
The cavum or 'hole-punch' cloud is just that: a hole in a cirrus cloud layer formed by super-cooled water droplets falling downward.
Sometimes called Kelvin-Helmholtz waves, these shapes form momentarily at the upper part of a cloud, taking the shape of breaking ocean waves.
The updated Cloud Atlas also accounts for manmade aerial phenomena including contrails, the vaporous streaks left by aircraft.
Learn about all the new classifications here and remember to never stop searching the sky, because, who knows, you might just discover a new type of cloud...