A dozen new cloud formations receive official recognition

23 Mar 2017

Cloudscape with altocumulus clouds in stratocumuliform. Image: artpritsadee/Shutterstock

The wonderfully named International Cloud Atlas has revealed a batch of newly recognised cloud formations, with rolls and waves galore.

The International Cloud Atlas (ICA) was last revised in 1987, with the 30 intervening years seeing an apparent clamour for a growing number of formations to be officially recognised.

The standout inclusion in this year’s revision is volutus, an entirely new ‘species’ that sees the formation of low, horizontal, detached, tube-shaped cloud mass, often appearing to roll slowly around a horizontal axis.

More colloquially known as a roll cloud, it is a species in both the stratocumulus and altocumulus genus. To explain this a little better, cloud classification is a terribly convoluted endeavour.

There are 10 genera: cirrus, cirrocumulus, cirrostratus, altocumulus, altostratus, nimbostratus, stratocumulus, stratus, cumulus and cumulonimbus.

Within these are species, each describing the internal structure of the shape of clouds – though the likes of volutus can act as a species of more than one genus.

Elsewhere, the rare wave-like asperitas cloud has been added to the list, which resembles the underside of a cloth that rests on top of a body of water, and is defined by endless ripples and dimples.

‘Special’ clouds recognised in the new ICA include flammagenitus (clouds generated from forest fires) and homogenitus (human-made or anthropogenic clouds, such as those that form over power station cooling towers).

Humanity’s fingerprints do not end there as, rather questionably, contrails (clouds formed from the vapour trail of airplanes) have been added to the new list, too.

The ICA is online, marking an obvious change from its 1987 prequel, with its release coinciding with World Meteorological Day (23 March).

The day, according to Rob Varley, chief executive of the UK Met Office, “provides a fantastic opportunity for everyone to appreciate the importance and value that the weather can bring to the globe”.

“Clouds play a key role in the function of our planet’s climate system and the naming of the new volutus species of cloud shows that we are continually learning and developing our understanding.”

Gordon Hunt was a journalist with Silicon Republic