Kelvin-Helmholtz clouds, also known as fluctus clouds, is a rare phenomenon that's easy to miss because it disappears so quickly. But its distinct water-like waves makes it a favorite among cloud ...

The wave clouds were crafted by a phenomenon known as Kelvin-Helmholtz instability, which occurs as a result of differences in air density in adjacent layers of the sky.

Kelvin-Helmholtz clouds occur when there is a temperature inversion with a warm, light (less dense) layer of air at the top of the cloud and a cool, heavier (more dense) layer at the bottom.

In the atmosphere, which acts similar to a fluid, this happens between two layers of different air densities. Kelvin-Helmholtz instability has also been spotted on the sun and Saturn.

Kelvin-Helmholtz clouds or fluctus clouds, as the formations are named, are very rare over Washington, according to KING 5 Chief Meteorologist Mike Everett.

Kelvin-Helmholtz wave clouds at Big Horn Mountains near Sheridan, Wyoming, Dec. 6, 2022. (Rachel Gordon) Kelvin-Helmholtz wave clouds at Big Horn Mountains near Sheridan, Wyoming, Dec. 6, 2022.

Kelvin-Helmholtz clouds or fluctus clouds, as the formations are named, are very rare over Washington, according to KING 5 Chief Meteorologist Mike Everett.