Support Provided ByLearn More
Planet EarthPlanet Earth

12 New Types Added to Cloud Atlas, First in 30 Years

The venerable International Cloud Atlas receives its first update since 1987.

ByTim De ChantNOVA NextNOVA Next
An asperitas cloud

Few reference books inspire such awe and wonder as the International Cloud Atlas. First published in 1896, the collector’s item is used by meteorologists, sailors, and admirers alike. Now, it’s available on the web for the first time, complete with 12 new types.

The web portal and new cloud types are both nods to the digital age. The former is obvious—reference materials are tailor made for the internet—while the latter is a result of digital cameras and smartphones.

In the past, new cloud types, especially rare ones, were difficult to document. Now, with the ubiquity of digital photography, nearly anyone can snap a high-resolution photo of an unusual cloud and sent it to a meteorologist for examination.

Among the new types added to the atlas are the wavy, mesmerizing asperitas cloud, the imposing, roll-like volutus cloud, and the hole-punch cavum cloud.

An imposing volutus cloud rolls over Racine, Wisconsin.

Support Provided ByLearn More

The revisions to the Cloud Atlas were inspired by a citizen science campaign to recognize the asperitas type. Here’s Matt McGrath, reporting for BBC News:

“Back in 2008, I thought the chances of this becoming official were really minimal,” said Gavin Pretor-Pinney, president of the [Cloud Appreciation Society].

“At first the WMO were saying they had no plans to do a new edition, but over time I think they began to realise there is an interest among the public in clouds and there is a need for that interest to be an informed one, there’s a need for this authoritative work.”

A cavum, or hole-punch, cloud

The only new species is the volutus cloud; the other additions are include five supplementary features, one accessory cloud, and five so-called “special clouds” that are dependent on local factors that lead to the formation of or change in appearance of a cloud. The World Meteorological Organization has a full rundown of the new types.

Another asperitas cloud

The new additions to the Cloud Atlas are so varied that it’s likely that keen observers have already witnessed at least one.

To see more photos of the new cloud types, head on over to The Guardian . And to dive into the science behind clouds—and try your hand at classifying them— don’t miss NOVA’s Cloud Lab .

Receive emails about upcoming NOVA programs and related content, as well as featured reporting about current events through a science lens.

Photo credits: fullswing/Flickr (CC BY-NC-SA) , Easydp/Wikimedia Commons (public domain), H. Rabb/Wikimedia Commons (CC BY-SA) , Agathman/Wikimedia Commons (CC BY)

Funding for NOVA Next is provided by the Eleanor and Howard Morgan Family Foundation.

Major funding for NOVA is provided by the David H. Koch Fund for Science, the Corporation for Public Broadcasting, and PBS viewers. Additional funding is provided by the NOVA Science Trust.