An unusual sight in the sky above Sydney over the weekend has baffled the masses, with many questioning what on earth it could be.
"Can someone explain [to] me what [that is]?" one observer wrote on TikTok on Sunday, after filming the extraordinary scenes playing out in front of them.
The video shows what looks to be a dark mass floating midair above the water, separate from the other clouds above it. The Sydney man who filmed the sight suggested it looks like "liquid metal" and believed it wasn't a cloud.
Wild theories emerge online
The video garnered thousands of comments from people equally intrigued with many sharing their thoughts. Some said the unusual mass resembled a UFO, while others said it was likely just air pollution. Many drew comparisons to a "dementor" from the Harry Potter series, which is a dark, soul-like figure that would glide through the air.
But most concluded the mass was in fact a scud cloud, a type of cloud that appears at low height above ground. It's usually detached and of irregular form.
"It's low-level moisture, it happens whenever there's a storm, it's basically a cloud," one said. But others weren't so sure.
"I don't think that's a cloud," one responded. "I just Googled scud cloud, scrolled through countless images, not a one looked like this," another agreed.
Scud cloud formation explained: 'Fairly extreme'
Martin Singh, from the School of Earth, Atmosphere, and Environment at Monash University, agreed "it is indeed a strange looking formation" but he confirmed it was a scud cloud, officially called a pannus — or at least something similar.
"Sometimes these clouds are formed when rain evaporates below a parent storm, moistening the air and eventually leading to a secondary cloud formation," he told Yahoo News Australia. "Under these conditions, they are not part of an organised updraft, and so they can take on a ragged appearance."
Scud clouds — which are pretty common — often have a "wispy and fractured appearance" he explained, but said the one shown in the video "is fairly extreme". He suggested why this might have been and said it could come down to a couple of things.
"My guess would be that it is partly the position of the sun which makes the cloud look so dark, and partly that the cloud is quite close to the observer, so you can see the details of the cloud edge better than usual," he said. He said it also looks like it's moving "quite quickly".
Although posted on Sunday, it's likely the scud cloud appeared in the sky on Saturday evening after a huge thunderstorm rolled over Sydney. The city copped heavy rain and ferocious winds reaching up to 50km/h at Kingsford Smith Airport. Newcastle, the Hunter Valley and the Central Coast were also affected.
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