Asperitas clouds: ‘Wavy’ clouds caused by thunderstorms seen across New Zealand skies

Asperitas clouds seen in Waimauku. Photo / Clare Nicholas

Expansive cloud formations that look like large swells are being seen across parts of Auckland today.

Photos of the clouds have been seen across Muriwai and West Auckland and look like upside-down mountains in the sky.

Metservice meteorologist Braydon White told the Herald the “wavy” clouds are called “Asperitas”.

“Asperitas form when there are waves in the cloud that cause the cloud base to lift up and down, a lot like waves in the ocean,” White said.

While the exact cause of the waves is “difficult” to say, White suspects it could be due to thunderstorm activity being seen out to the west of New Zealand.

It’s also related to the wet weather being experienced across the country today.

Asperitas clouds have been seen across New Zealand today. Photo / Steph Weenink

“The rapid updrafts and downdrafts of air in a thunderstorm can send ripples of waves out into the atmosphere, like a stone in a pond.”

He said these waves can cause the cloud to be thinner in some areas and thicker in others, which changes how much light filters through from the sun.

“[It] gives it that wild swell look.”

Meanwhile, people on a Waimauku and Muriwai public social media group posted photos of the cloud, confused about what it was.

Some thought it was pretty, cool, or strange, while some compared it to an appearance of “tornado clouds”.

Clare Nicholas told the Herald she saw the cloudy formation before heavy rain started in Waimauku.

She posted her image on the public page, which received over 600 reactions in five hours.

“It was quite an incredible sight, [I’ve] never seen it before.”

Huapai resident Steph Weenink echoed a similar sentiment and also said she’s “never seen clouds like this” before.

Asperitas clouds seen in Waimauku. Photo / Clare Nicholas

Meteorologist Braydon White said the thunderstorms out to sea are part of a “much larger frontal system”, that has been moving into the country today, and bringing rain and wind alongside it.

The system moves over New Zealand through today and overnight tonight.

“By the end of tomorrow, much of the country is looking sunnier, with just a few showers lurking.”