Varying levels of illumination and thickness of asperitas clouds can lead to dramatic visual effects. (Photo: WikiRigaou/Wikimedia Commons)
Excerpt:
We stare at clouds all the time, whether trying to figure out what they look like or if they’re bringing rain. Yet most of us know very little about clouds, let alone how to identify them.
The World Meteorological Organization (WMO) keeps a cloud atlas that divides clouds into genera, species and varieties. Some clouds have multiple “varieties” and some have “accessory” clouds that appear with or merge with bigger clouds. Specific conditions can even create special clouds of their own.
In short, clouds are a rich tapestry in the sky that changes every day.
Cloud genera
These are the 10 most typical forms clouds take. The WMO notes that the definitions don’t encompass all possible cloud permutations, but they do outline the essential traits to differentiate one cloud genus from another, especially those having similar appearances.
