Appearing as waves in the sky, these rare clouds were spotted by a user in Hampshire earlier this month. Let's look at what makes them special.

Known as Kelvin-Helmholtz wave Clouds, these types of cloud only last for a few minutes before dissipating without a trace, which is exactly what user Sue Davies reported suggesting that the waves had lost their shape entirely shortly after the picture was taken.

Kelvin-Helmholtz clouds appear when the air is very unstable. They form when faster-moving, warm air flows over slower-moving, colder and denser air.

If the speed at which the warm air travels over the colder air is fast enough, the undulating wave-like formation in the cloud appears.

These types of clouds can form anywhere that that the right conditions appear, just be quick with the camera to catch them before they vanish!

If you have spotted any odd or interesting clouds recently please send them in for us to take a look at next week! Use our uploader or send them direct through the app by tapping the camera icon.