No new cloud type has been officially classified since 1951 but Gavin Pretor-Pinney who runs the Cloud Appreciation Society believes that there is a new cloud that deserves international recognition. He calls it asperatus, which means rough in Latin. [via]
Top: Schiehallion, Scotland.
Middle: Cedar Rapids, Iowa, US.
Bottom: Hanmer Springs, South Island, New Zealand. [Previously posted here.]
Apparently the unusual cloud formation is benign, not related to precipitation, violent weather or mass extinctions.