Laurence Dyke filmed this wonderful time-lapse of asperitas clouds over Disko Island in the west of Greenland. He was a glaciology PhD student at Swansea University at the time, and was in Greenland to attend a summer school for PhD students organised by the University of Bergen, Norway. “The cloud appeared the day we arrived on the island,” Laurence explained, “after we’d travelled from the mainland by boat through the tail end of a storm.” Laurence now works in Copenhagen, Denmark, for the Geological Survey of Denmark and Greenland. “I’d never seen clouds like this before,” he added. “The formation was all the more impressive because the wind at ground level was still but the clouds were really shifting.”

This is a beautiful example of a new classification of cloud, which has finally been accepted by the World Meteorological Organisation as an official cloud type. Back in 2009, the Cloud Appreciation Society first proposed that this cloud be added to the classification system. We suggested at the time that it should be called ‘asperatus’, meaning ‘roughened’ in Latin. The WMO have now announced that it will be included in the new edition of their International Cloud Atlas, due out later this year or the beginning of next. This will be the first new cloud classification since 1951. The WMO have decided that the name be changed to the Latin for ‘roughness’. The new name for this cloud is therefore confirmed as ‘asperitas’.

Anyone who is interested in obtaining a broadcast quality version of the video without watermark should contact Laurence Dyke directly at info@laurencedyke.com.