“They looked like space ships to me,” Cathie Simpson said. 

The office manager was leaving work at about 12:45pm when she they caught her attention and she snapped a picture on her iPhone to find out more.

The answer: lenticular clouds. Stationary, lens-shaped clouds which form in the troposphere, normally in perpendicular alignment to the wind direction.

“Basically, they're formed when air is lifted over ranges – typically by stronger winds – and a wave is formed in the flow,” Bureau of Meteorology forecaster Stephen King said.

“The clouds then tend to form in the peaks of these waves.

“They were also visible around the Melbourne area.”

Because of their shape, lenticular clouds are sometimes cited as explanations for UFO sightings. 

Did you snap any of these strange clouds or have you taken any photos of interesting cloud formations? We’d love to see them. Share them with us via Facebook, tag them #BorderClouds on Instagram or email them to scott.hazlewood@fairfaxmedia.com.au