In 1802 a London pharmacist, Luke Howard, made the first classification of clouds based on 3 main types: wispy cirrus, puffy cumulus and sheet-like stratus. Since then the classification has grown into 10 main types of cloud, with many varieties, although no new type of cloud has been recognised since 1953. However, Gavin Pretor-Pinney, who runs the Cloud Appreciation Society, believes he has identified a remarkable new cloud type that looks like a churned up sea in a violent storm, and he has named it asperatus, from the Latin verb aspero meaning “to roughen up” or “agitate”.
Photos of the cloud were sent in by cloud society members from many different parts of the world, including Scotland, and have been submitted to the Royal Meteorological Society. The location, conditions and dates when the clouds were seen is now being collated to understand what was happening in the atmosphere to create them. That analysis could take a few months and if it appears that this is indeed an unrecognised cloud, the findings will be submitted to a committee of experts at the World Meteorological Organisation based in Switzerland for official recognition.
Identifying clouds is a fascinating science and tells us much about how the atmosphere behaves and what weather they might signal. To help with this, Gavin Pretor-Pinney has written a pocket-sized book, The Cloud Collector’s Handbook (Hodder & Stoughton).