Spiral clouds wow near Mt Taranaki

A lenticular cloud formation over Taranaki. Photo / Alexander Spires and Hannah Chapman-Carr

A bizarre-looking cloud formation near Mt Taranaki yesterday had people whipping out their phones to snap pictures.

The clouds appeared to form a spiral or a stack of plates, and several posters wondered what was causing the strange spectacle.

MetService meteorologist Tui McInnes said they're known as lenticular clouds.

"It's caused by the air interacting with the terrain. It's actually quite common over single isolated [mountain] peaks."

A lenticular cloud formation over Taranaki. Photo / Alexander Spires and Hannah Chapman-Carr

The clouds are formed as the air moves over the mountain in a wavelike motion, he said. However the clouds are often displaced from the mountain or other terrain, which makes them look "odd", McInnes said.

"They're common over the Southern Alps, especially in northwesterlies - you quite often see them downwind of the mountain."