After years of lobbying, the World Meteorological Organization (WMO) granted asperitas formations a spot in the official cloud canon. The change was part of an update to the International Cloud Atlas released for World Meteorological Day on March 23, 2017.
The first iteration of the cloud atlas, published in the late 19th century, laid down the scientific standards for the monitoring and measurements of clouds and other meteorological phenomena. It formalized the system of taxonomy introduced by amateur cloud-spotter Luke Howard [PDF] in 1802, which mirrored the classification of plants and animals by sorting clouds into 10 major types, or genera, then splitting them further into varieties and species.
The last edition of the atlas was published in 1987. The clouds may not have changed since then, but the world has, and the WMO wants to keep up. The newest edition is all digital and includes measurements and data from 191 different countries and territories. It will also feature one new species—the volutus, or tube-shaped cloud—and five supplementary features, including asperitas.
The inclusion of asperitas is a point of pride for Cloud Appreciation Society founder Gavin Pretor-Pinney, who says members have been sending in photos of asperitas-covered skies for more than a decade.
“Ever since we first noticed distinctive turbulent waves of cloud back in 2006 in images sent from Cedar Rapids, Iowa, U.S., we have argued that this formation did not easily fit within the existing naming system,” CAS noted on its website. “So we are very pleased that now, almost 10 years later, asperitas is finally being accepted as an official classification by the World Meteorological Organization.”
The taxonomy of clouds may sound fluffy to laypeople, but experts like WMO secretary-general Petteri Talaas take it very seriously. “If we want to forecast weather, we have to understand clouds,” he said in a statement. “If we want to model the climate system, we have to understand clouds. And if we want to predict the ability of water resources, we have to understand clouds.”