Watch: Gigantic cloud structure rolls across Argentina, social media reacts in awe

A video of a gigantic cloud structure near Buenos Aires in Argentina triggered social media reactions from some thinking aliens were on their way to another claiming it was fake news.

The footage, obtained by Reuters and shot by Capitan Marcelo Lopez, shows the enormous layered white cloud bank dividing the sky over Zarate, 90 kms north-west of Buenos Aires on Wednesday (local time).

Users on social media were shocked by the footage shot from on-board of a ship.

"[It's] like Independence Day," a woman said with another tweeting it could resemble the border wall US President Donald Trump hopes to build.

"Look, it's the mother ship coming in for a landing," said one user whereas someone else was said the image was nothing more than a lucky shot, citing: "Someone just happened to be there with a camera".

Other Argentinians shared pictures of the cloud with many explaining the phenomena as a "shelf cloud" - a low-hanging, distinguished formation also known as an arcus cloud.

An alert for strong winds was forecast for the area as an intense front advanced with strong gusts of wind, according to Reuters.

Newshub.