Footage shows the moment locals discovered delicate frost flowers spread on the surface of a frozen lake.

The footage shows thousands of frost flowers, an odd phenomenon where frost grows from imperfections in the surface ice amid extreme sub-zero temperatures, that were captured on Thursday, December 7.

Mr An recorded the rare sight in the city of Shouzhou, in Shanxi Province, northern China.

He said: 'I don't know what happened. This is my first time seeing it. This kind of scene is not common.'

Frost flowers are ice crystals most commonly found growing on young sea ice and thin lake ice in cold and calm conditions.

They are similar to hoar frost and usually grow in patches between three and four centimetres (1.1 and 1.5 inches) in diameter. These mesmerising formations, according to reports, appear when the atmosphere is much colder than the underlying ice.