A long day of paddling on the Lower Missouri River in Missouri, US was halted for Annie Laurie Balthazar (Member 64,354) due to a dramatic thunderstorm.

These pouchlike cloud features that she spotted backlit by lightning are mamma, sometimes also called mammatus, from the Latin word for ‘udders’._ _They can appear beneath many cloud types, but the most pronounced, like these ones, form on the underside of the huge anvils, known as incus, that spread out at the top of mature Cumulonimbus storm clouds.

Annie’s cloudspotting skills came in handy that day. She was able to paddle to the safety of the shore and find a secure camping spot. From there, she could sit back, watch the show, ‘and marvel at how small we really are!’.