This remarkable night-time view that could be easily mistaken for a tall mountain towering over the horizon is actually a giant mass of dark clouds that had descended from the sky.

The strange 'cloud wall' was spotted over the evening sky of Changchun, in Jilin Province, north-eastern China, on December 7.

A local female resident captured the unusual sight while travelling in a car straight towards it.

The 'wall', masked behind relative darkness and oddly even edges and slightly taller towards the middle, looked more like a majestic mountain than a sky formation.

The phenomenon, scientifically known as altostratus clouds, reportedly lasted for nearly 30 minutes before the clouds dispersed.

Meteorological experts described the event as a rare weather occurrence caused by the mixing of warm and cold air masses.

When these two masses converge, it results in water droplets and ice crystals gathering in the air to form a distinctive cloud layer.

The regular shape and smooth boundaries of this cloud layer are mainly attributed to significant wind shear at high altitudes.

The shape and colour of this layer depend on the size and quantity of water droplets and ice crystals.

Experts added that the phenomenon is not uncommon, and similar situations happen in some regions every winter.