Surf's up: Rare wave cloud captured in Bay of Plenty sunset

"Magic". This cloud formation was captured at sunset over the Kaimai Range. Photo / Cade Hughes

A rare wave cloud formation captured on the brink of sunset in the Bay of Plenty has been described as "magic".

Cade Hughes said he and his wife were relaxing on the deck of their Omokoroa home overlooking the Kaimai Range about 5.15pm on Wednesday when their daughter said to them: "Wow, look at it this time."

"Every sunset is different over the Kaimais," Hughes said.

"So we turned around and were blown away. We've never experienced anything in person like that before. I grabbed my phone and snapped a couple of photos."

The wave cloud was seen by many. Photo / Cade Hughes

Hughes, who works as a media specialist for NZME, said the wave formation of the cloud lingered for three to four minutes before losing its shape.

"But then they came back for a few minutes. It was quite intriguing."

Hughes said the backdrop of the sunset made the sight of the strange cloud "magic".

"Honestly, the photos probably don't do it justice."

Serena Stock was also taken aback by the cloud.

Stock was sitting in her lounge talking with her daughter on the phone when she saw a strange image on her television. Once she realised the image was a reflection of the cloud she went out to her deck and took photos before the cloud lost its formation.

"I have seen these type of wave clouds three times before, but this was the best display," she said.

"I love clouds and often take photos of them. Whether it's the whimsical aspect like seeing pictures or a wind artist at play or dramatic contrasts of storm clouds," she said.

The cloud formation was captured about 5.15pm over the Kaimai Range. Photo / Cade Hughes

Metservice communications meteorologist Lewis Ferris said the photos depicted "a fantastic display of kelvin-helmholtz clouds".

"These are quite a rare cloud," he said.

Ferris said the most important condition for the clouds was that there was "wind shear", meaning the wind higher up was faster than wind below.

"That's why the top of the cloud appears to fold over.

"Another condition is that there is sufficient atmospheric instability which allows the two layers of windspeed to interact."

Ferris said the clouds tended to show up in lines such as the one photographed.

"These clouds are localised phenomena so it's possible this was the only one in New Zealand last night."

Globally, Kelvin-helmholtz clouds are considered an extremely rare phenomenon and named for Lord Kelvin and Hermann von Helmholtz, who studied the physics of the instability that leads to this type of cloud formation.