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Impressive breast-shaped mammatus clouds seen in post-storm Melbourne sky

By Tynan King, Wednesday December 20, 2017 - 19:12 EDT
Audience submitted image
Social media users posted photos of the oddly shaped clouds, with this one taken over Mount Evelyn. - Audience submitted

Melbourne residents observing Tuesday night's storms might have seen more than they bargained for.

The severe thunderstorms which caused flash flooding and leaving tens of thousands without power.

They hit Melbourne's CBD around dinner time, just as people were preparing for a night in front of the television (or their smartphones and tablets).

Pulled from their screens, residents turned their gaze to the dazzling electrical show in the sky.

When the storm passed, they noticed oddly shaped clouds and took to social media to share their finds.

Clouds shaped by cold air



Bureau of Meteorology forecaster Dean Marramore said the circular clouds were called mammatus clouds.

"It's a Latin name and it means breast, udder or mammary gland," he said.

"Basically, that's what they look like."

Mammatus clouds get their shape when cold air sinks below the cloud.

"They normally form on the back of severe thunderstorms like the one we had last night," Mr Marramore said.

"You get a lot of air rise up into the storm and then some of it tries to sink back down."

Mr Marramore said the uncommon cloud formation generally lasted between 15 and 20 minutes.

He said Tuesday's mammatus clouds were particularly "impressive" because they occurred as the sun was setting.



Not all cute and fluffy

The severe thunderstorms caused widespread damage across Victoria.

The state's north-west and central districts were the hardest hit, with 100 kilometre-per-hour winds bringing down trees and powerlines.

Homes were damaged, roads were cut off by fallen trees and tens of thousands of properties lost power.

Large hail hit in some areas and there was flash flooding in Melbourne, where 20 millimetres of rain fell in 15 minutes.

The clean-up continues.


- ABC

© ABC 2017

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