Dazed sky-watchers in the US province of Wyoming have snapped photographs of an uncommon cloud development crashing across the skyline like sea surf.
"This was unique and I quickly realized I expected to catch it," said neighborhood Rachel Gordon.
The surging peculiarity was apparent on Tuesday over the peak of the Bighorn Mountains from the city of Sheridan.
Known as Kelvin-Helmholtz unsteadiness, they structure when a quicker stream of air moves above rising air beneath.
Ms. Gordon told she took the pictures from her indirect access prior to presenting them on the Facebook page Wyoming from The Perspective, said: "It was a striking second.
"I'm simply happy others can partake in the experience now, as well."
The UK-based Cloud Appreciation Society depicts such arrangements as the crown gem in many cloud spotters' assortments.
Otherwise called fluctus mists, they are viewed as a potential motivation for Van Gogh's painting Brilliant Evening.