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.
