Parts of Australia's east coast are flooded again just four months after historic floods in March.

The situation is sometimes so dramatic that the government has declared the floods in the state of New South Wales a natural disaster in order to be able to free up funds for the flood victims more quickly.

The metropolis of Sydney is particularly affected.

In the metropolitan area with the world-famous opera house, entire areas were flooded meters high.

In just four days, more precipitation fell than in London in a whole year, meteorologists calculated.

That makes it clear what kind of torrents came down from heaven.

A powerful low-pressure area between Australia's east coast and the North Island of New Zealand is responsible for driving humid air and heavy waves onto the coast of New South Wales.

Bush fires and floods on an ever increasing scale

"Because of previous above-average rainfall in summer and parts of autumn, this rain falls on wet soils and full reservoirs," climate expert Mark Howden of the Australian National University wrote in the Sydney Morning Herald.

The result: the rivers swell at lightning speed and burst their banks.

Howden warned that such extreme weather events will become more frequent in the future "if we don't act now".

A clear plan is needed quickly to combat the effects of global warming.

Because Australia is particularly suffering from the consequences of climate change - heat waves, bush fires and floods on an ever greater scale and at ever shorter intervals are the result.

In March, there were devastating floods in Sydney and large parts of New South Wales and Queensland.

Many Australians are still suffering from the devastating effects of the historic floods and are once again fearing for their existence.

"We can't go through this again"

The crisis is the first major test for Prime Minister Anthony Albanese's government.

The Labor chief, who has only been the new prime minister since May, has made the fight against climate change a central point of his agenda.

In order to push this forward more quickly, he is planning a new "Mega Ministry for Climate Change, Energy, Environment and Water".

The conservative previous government of coal supporter Scott Morrison, on the other hand, was heavily criticized for its passive climate policy.

Albanese, who is expected to return from a trip to Europe on Tuesday, wanted to travel to the disaster area in person as soon as possible.

Meanwhile, those affected were desperate.

"We will sell.

We can't go through this again," media quoted a man named Darren Morgan, who has lived in the Sydney suburb of Lansvale for more than 20 years, as saying.

His house was hit twice by flash floods within 48 hours.

Almost 20,000 households without electricity

A total of 50,000 people had been evacuated by Tuesday.

Hundreds of residents called for help overnight.

The emergency services moved out again and again to empty houses and save people.

Almost 20,000 households were without electricity.

Streets were under meters of water, bridges were washed out.

Rail traffic was partially interrupted after landslides.

Some areas, like the Congewai Valley in the Hunter region, were cut off from the outside world because of the water masses.

It will probably be days before the area is accessible again, it said.

"The main road in and out of the valley was washed away overnight," said resident Jill Crawford-Lane.

"Every family here is affected, we can no longer even reach our neighbors who live only a kilometer away."

Regional Premier Dominic Perrottet urged people to follow the authorities' instructions.

"If there is an evacuation order, please leave your house." The crisis is "anything but over," said the politician: Heavy rain is also expected in parts of New South Wales for the rest of the week.