A huge storm dubbed a 'cloud tsunami' has formed off Sydney's Bondi Beach prompting severe weather warnings. The low-hanging cloud formation, known as a 'shelf cloud' which typically forms under severe thunderstorms, could cause large hailstones, heavy rainfall and strong winds.

A similar cloud system caused rush-hour flooding when it moved over Sydney in March 2014.

Photographer Nick Moir, of the Sydney Morning Herald, told Sky News: "Shelf clouds are pretty common but to get them so big and coming right up the coast of Sydney is not that common - you get a couple a year.

"This is a pretty significant one, plus it's been a warm day, a lot of people are out - particularly at Bondi - and this huge mammoth storm just started rolling up the coast and of course social media went atomic."

He explained that the storm is moving rapidly through Sydney. "Generally, with severe storms, often flash flooding is actually the real killer - not so much the tornadoes or massive hail. It has moved through Sydney and is moving up the coast at the moment. It's moving very rapidly out to the ocean so by tomorrow (Saturday) things should have calmed down."

Residents have been warned to stay away from power lines, trees and drains, however locals couldn't help but stop to marvel at the spectacular sight. Eyewitness Hannah Murphy told CNN. "People were running from the streets to capture the unbelievable cloud formation,"

Photographers and tourists have also been capturing dramatic images of the phenomenon and sharing them on social media. Posting an image capturing an avalanche of clouds in Kingsford, Robbi Bishop-Taylor wrote: "First #tornados in Melbourne, now cloud #tsunamis in Sydney. Australian weather: you are terrifying! #sydneystorm "

The Australian Bureau of Meteorology issued a severe thunderstorm warning as it blew ashore mid-afternoon, cautioning large hail, heavy rain, and damaging winds were possible.

"All the dynamics of the atmosphere came together for a short time," Mohammed Nabi, a Bureau of Meteorology forecaster, told the Sydney Morning Herald. "It was a short, sharp event."

As the storm passed, Sydney's temperature dropped from 83 (28.3 Celsius) to 69 degrees (20.6 Celsius).

Footage captured by TwelveMedia shows the storm resembling a giant wave rolling over Sydney.

Just caught this storm coming in from the south. Look out Bondi! @canonaustralia #sydneystorm #canon5Ds #24-105mm

A photo posted by guysebastian (@guysebastian) on