But few are fortunate enough to see Kelvin-Helmholtz clouds, which look like a pattern of ocean waves in the sky. Kelvin-Helmholtz clouds, also known as fluctus clouds, is a rare phenomenon that's ...

It's a first for me." Anne Wilkie posted on X. What she saw was a Kelvin-Helmholtz wave cloud, named after Hermann von Helmholtz, who discovered the atmospheric instability that leads to this ...