Sydney recorded its wettest year in 164 years as authorities braced for major floods in Australia's east, with more heavy downpours expected to fall over the next three days.

With almost three months of 2022 still to go, Australia's largest city has recorded 2,200mm of rain in a year for the first time since records began in 1858.

By yesterday afternoon, Sydney had received about 2,213mm of rainfall for the year, surpassing the previous record of 2,194mm set in 1950, official data showed.

More than 58mm fell over five hours since 9am local time, the Bureau of Meteorology's (BoM) live data showed.

More downpours are forecast for the rest of 2022, as Australia's east coast remains in the grip of a rare third straight year of the La Niña weather phenomenon.

"Heading into late spring and summer, we're still in this active La Nina period so we can expect more and more rainfall and that does increase the risk of flooding," BoM forecaster Jonathan How told ABC television.

During the past two years, floods have struck Sydney's suburbs three times, forcing tens of thousands of people to flee their homes.

With a wild weather system expected to dump heavy rains through the weekend across a wide swathe of Australia's east, authorities warned Sydney residents to watch out for flash flooding and stay away from flooded roads.

By yesterday afternoon, Sydney had received about 2,213mm of rainfall for the year, surpassing the previous record of 2,194mm set in 1950, official data showed

Many dams and rivers are already at full capacity.

The New South Wales state government has committed to raising the height of the wall at Sydney's Warragamba Dam, which supplies 80% of the city's water, to help prevent future floods.

'More water coming'

Some of the state's rural inland towns were already flooded, with television footage showing damaged roads and residents moving farm animals to higher ground.

New South Wales emergency crews said there were 47 flood warnings in place across the state, with moderate flooding expected in parts of Sydney on Saturday.

The situation will only get more dangerous over the next few weeks, emergency services spokesperson Scott McLennan said.

"Are we at the worst? We don't know, but we do know that there is more water coming," Mr McLennan told the Australian Broadcasting Corp.

Extreme weather

The east coast flooding catastrophe in March - caused by heavy storms that devastated parts of Queensland and New South Wales - claimed more than 20 lives.

Tens of thousands of Sydney residents were ordered to evacuate in July when floods again swamped suburbs on the city's fridge.

People had to leave their homes in towns across the New South Wales Northern Rivers region
in March, as heavy rainfall caused flash flooding

Australia has been at the sharp end of climate change, with droughts, deadly bushfires, bleaching events on the Great Barrier Reef and floods becoming more common and intense as global weather patterns change.

Australia's east coast has been repeatedly lashed by heavy rainfall in the past two years, driven by back-to-back La Nina cycles.

A rare third consecutive La Nina was recently declared, prompting further rain and flood warnings for the coming summer.

More Climate Change stories

Higher temperatures mean the atmosphere holds more moisture, unleashing more rain.

Australia's Insurance Council has previously estimated more than Aus $5 billion (€3.27 billion) worth of catastrophe claims were made in 2022.

Catastrophic bushfires swept through huge chunks of New South Wales in the "Black Summer" of 2019 and 2020, scorching 5.5 million hectares - about 7% of the state's total landmass.