Noctilucent clouds are made mostly of ice particles that may form when water vapour condenses onto atmospheric dust.

The ice particles fall into a ring shape because each one follows a similar orbital path.

The thundercloud had grown so high into the sky that the top half of the cloud was made up of countless billions of ice particles.

A droplet of water freezes into ice particles, making a snow crystal.

With repeated yo-yoing up and down the cloud, these ice particles grow into hailstones, which eventually crash to earth in showers of hail.