It’s time for you to look up at the sky more often.
If you did, you might catch a volutus, or roll cloud, which looks like a tube that appears to be spinning along its horizontal axis. Or perhaps you’ll get really lucky, and see a dramatic-looking asperitas cloud, from the Latin word for roughness. These resemble a rough sea’s surface, as seen from underwater.
The volutus and asperitas are but two of the 11 new cloud classifications included in the new edition of the International Cloud Atlas that the World Meteorological Organization (WMO) will publish online on Thursday.
This is the first update to the cloud atlas since 1987, and some of the new clouds featured were the subject of concerted, multi-year lobbying campaigns. This also marks the first time the guide is being published online.
That’s right — there are cloud lobbyists. Well, sort of, anyway.
The Cloud Appreciation Society, a group of about 43,000 cloud enthusiasts scattered throughout 110 countries, has pushed for the recognition of asperitas as a new type of cloud since 2006.
Gavin Pretor-Pinney, the society’s founder, said that these clouds first came to his group’s attention more than a decade ago, when a dramatic display occurred in the skies above Iowa. He describes such clouds as resembling a turbulent sea as viewed from below the water’s surface.
“I wasn’t ever really expecting the new classification of cloud to really become a newly classified cloud under the WMO,” Pretor-Pinney said in an interview.
He said the society helped document the asperitas formation using an iPhone app called Cloudspotter that allows users to take pictures of clouds and guess what types are in the image. Experts then respond to them with the proper classification.
“The important thing… is that this gave us a great body of examples of the asperitas formation, taken in different places around the world,” Pretor-Pinney said. So far, the group has gathered 280,000 cloud images through the app, he said.
In addition to the asperitas classification, the new atlas also contains new names for clouds that were already well-known to weather geeks around the world, including the Kelvin-Helmhotz cloud and the hole-punch cloud, also known as a fallstreak hole. Officially, these will now be known as fluctus and cavum, respectively, though meteorologists may exhibit a fondness for the less formal terminology.
Another “accessory cloud,” which is well-known to tornado chasers, will now have the Latin name flumen. Chasers call it a “beaver’s tail,” owing to its shape and placement within a severe thunderstorm.
In addition, the new atlas puts forward five “special clouds” with tongue twisting names like “cataractagenitus,” “flammagenitus,” “homogenitus” and “silvagenitus.” These clouds are created by localized factors such as large waterfalls, heat from wildfires and engine exhaust from high-flying aircraft, which are also known as contrails.
Pretor-Pinney, who has written a book about clouds, thinks deeply about the cultural significance of the formations above.
“The sky is of course the most chaotic and boundless of nature’s displays. It’s the reason why we love it, the sense of it being free and unboundable,” he said. “Of course, humans like to contain things, we like to contain things in our minds especially…. That is what this classification system, this naming system is all about.”
“Clouds mock our ability to do that because they’re in constant flux, a constant change.”
Even with the new cloud types, there’s no reason to worry: The 10 main cloud species you learned in school will remain the same, including cumulus, stratus and cirrus.
Pretor-Pinney says the new cloud atlas will help people focus on what’s going on above them, which given the wealth of stressful political news lately, may be a much-needed break.
“I think it’s good for your soul,” he said of cloud watching.
While the atlas has value in providing a standardized way of classifying clouds that will be used by weather observers worldwide, it may also help turn more eyes skyward.
“Ultimately from my point of view, in terms of the general public, it’s about getting people more engaged with the sky.”