Rainfall set to peak as weather systems collide
Areas of Australia that have seen their worst flooding in decades are bracing for more heavy rainfall, with the peak expected on Tuesday.
The entire coast of New South Wales has been put on alert, with troops and hundreds of volunteers deployed.
Roads and bridges have been cut off, cars and signs submerged, livestock marooned and schools closed.
PM Scott Morrison told MPs there was "serious risk still ahead" and weather officials said "it's far from over".
New South Wales (NSW) Premier Gladys Berejiklian said no deaths had yet been reported - "a miracle given what we have been through".
In pictures: Australia's 'one-in-a-50-year' flood
Some 18,000 people have been evacuated so far in the state, which is Australia's most populated with eight million residents.
What is the latest forecast?
The heaviest rainfall for the worst-affected state of NSW is expected overnight into Tuesday morning, as two major weather systems collide. The southern coastal areas could be the worst hit this time.
A tweet put out by Australia's Bureau of Meteorology said an area as large as Alaska - stretching from the NSW coast back to the southern Northern Territory - was now being affected by weather warnings.
media captionBBC Weather's Chris Fawkes explains why New South Wales has been hit with such heavy floods
In all, 10 million people are under warnings in every state and territory except Western Australia.
A low pressure weather system that has been inundating the NSW coast for days has now been met by another weather system inland that is moving east.
The bureau has forecast "increased rainfall, strong winds, damaging surf and abnormally high tides" in New South Wales on Tuesday.
"It may have been going for days but unfortunately this situation is far from over," the bureau tweeted.
Satellite image showing extent of flooding in western Sydney region on 21 March
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Its flood manager, Justin Field, said: "I've been a flood forecaster in the bureau for 20 years and this is probably the worst flooding that I've experienced and I've had to forecast.
"We've got a flood watch that covers all the way from the Queensland border down to the Victorian border."
PM Morrison told MPs on Monday: "Across NSW, 1,400 first responders have conducted over 700 flood rescues and responded to over 7,500 requests for assistance."
He added: "This is an ongoing situation that is evolving and is extremely dangerous."
Dogs are transported to safety in inflatable boats in Sydney
image captionDogs are transported to safety in inflatable boats in Sydney
The military is being deployed to help with search and rescue, in what has been called a "one-in-50-years event".
Some areas have seen close to a metre in rainfall.
But the bureau did predict some respite, tweeting: "Most areas of New South Wales will see a clearing trend early Wednesday as a drier airmass moves into the region."
What has been the damage so far?
Days of torrential downpours have caused rivers and dams to overflow around Sydney - the state capital - and in south-east Queensland.
Some 200 schools in NSW will remain shut on Tuesday as the peak rainfall hits.
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People in more than 15 mostly low-lying areas have been ordered to evacuate and a similar number have been given evacuation warnings.
An order requires people to seek shelter with family or friends well away from flood impacted areas, or in a special centre. The warning tells people to prepare for an evacuation order.
There have been some 15,000 evacuations from the Mid-North Coast and a further 3,000 in Sydney, officials said.
Areas around the Colo and Hawkesbury rivers are of particular concern. They are seeing the worst flooding since 1961.
Satellite image showing extent of flooding around Port Macquarie, New South Wales, on 21 March
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Scott Donnellan, a Presbyterian minister in Port Macquarie, told the BBC some people had toughed it out when the evacuation orders came but had to "abandon ship" when the water reached waist height.
He said the community was pulling together but was expecting "one final punch" from the weather.
Among the incidents that have happened:
The Warragamba Dam, Sydney's main water source, spilled over for the first time in five years. It reached a peak daily discharge on Sunday of 500 gigalitres - equivalent to the volume of Sydney Harbour
A 37-year-old woman in labour was airlifted to hospital after becoming trapped by flooding on the Nepean river
Video on social media showed an infestation of spiders on fences and walls in western Sydney as they tried to escape the rising waters
In Port Macquarie's North Shore, one resident was filmed dragging a stingray through what was his front lawn
On Sunday a young couple saw their house north of Sydney swept away by flash floods on what should have been their wedding day
PM Morrison has offered a one-off federal government payment of A$1,000 ($775; £560) per eligible adult and A$400 per eligible child for those seriously affected by the floods.
From fires to floods
The intense summer of rain and floods in eastern Australia is a stark contrast to a year ago, when many of the same areas were scorched by mammoth bushfires and ravaged by drought.
This side of the continent is currently experiencing a La Niña weather pattern, which typically brings more rainfall and tropical cyclones during summer.
Two of Australia's three wettest years on record have been during La Niña events. Typically a La Niña sees a 20% increase in average rainfall from December to March in eastern Australia.
Scientists say that climate change is also intensifying La Niña's impact, and making weather patterns more erratic.