The floccus species of cloud is one that’s hard to spot – not because it’s rare, but because floccus clouds are easy to mistake for other cloud forms. The name comes from the Latin for some ‘fluff’ or a ‘tuft of wool’, which doesn’t exactly narrow things down when it comes to clouds.

So what makes a floccus cloud a floccus? It is a form found in several of the ten main cloud types, characterised by the cloud elements having ragged, torn bases and rounded mounds at their tops. For the mid-level form, Altocumulus floccus, one way of identifying them is with the appearance of ice-crystal streamers known as virga, which can often be seen descending from them.

Sara Goodnick (Member 50,827) spotted these Altocumulus floccus virga over Fort McDowell, Arizona, US. ‘Do clouds create their own firework displays?’ she asked. ‘These ones appear to be celebrating something.’