From drought to deluge - wide areas of NSW and Queensland have been swamped by torrential rain that forced thousands from their homes and left two people missing, feared drowned.
A young couple was believed swept away on the Gold Coast as up to half a metre of rain turned roads into rivers, stranding motorists and flooding cars and homes.
In northern NSW, 3,000 people were told to evacuate their homes as Lismore prayed a new levee would save the town centre from inundation.
Elsewhere, record rains forced flights to be cancelled or delayed and prompted flood warnings for major rivers from mid-north NSW to southern Queensland.
More rain has been forecast for parts of NSW and Queensland, bringing hope for many parched areas, before clearing.
On the Gold Coast, more than 400 millimetres of rain was dumped in around 24 hours, exceeding the amount that fell before devastating floods in 1974.
Carrara recorded a massive 590mm over 36 hours.
A Counter Disaster and Rescue Services spokeswoman said 67 people were evacuated from their homes, while many apartment basement car parks were flooded.
Motorists were trapped in cars, homes were damaged and the major Gold Coast shopping centre Pacific Fair was closed down.
Meanwhile, a search is continuing for a man aged 25 and woman, 21, feared swept from a causeway into the Coomera River.
The search was launched after a call was received about 2am from a driver saying water was pouring into their car on the causeway, a police spokeswoman said.
"The mobile then cut out," she said.
People were warned to stay at home as few Gold Coast suburbs escaped the flooding.
There were also calls for help from water-damaged homes in Brisbane, Ipswich and Beaudesert.
"We haven't seen anything like this since the 1974 floods - there have been landslides and people's phones aren't working," said Gold Coast City Council spokeswoman Daphne McDonald.
Flooding shut down the Gold Coast Airport at Coolangatta and subsequent flight delays were felt in Sydney too.
"The runway is flooded and so are the taxiways - it is too dangerous for any aircraft and we are not allowing any landings," an airport spokeswoman said.
Across the border in NSW, the town of Lismore was the worst hit, with more than 500mm of rain falling in parts of the catchment.
As the Wilson River that flows through Lismore began rising, the State Emergency Service told 3,000 residents to leave their homes for evacuation centres.
Authorities had predicted the river would peak at 10.4 metres, just centimetres below the top of a new, 11-metre-high, $19 million levee built to protect the town centre.
But authorities have downgraded their flood warnings and it appeared Lismore would escape the worst of the flooding.
"There are no concerns about the levee," said SES spokesman Steve Delaney.
Lismore's worst flood was in the 1950s, when the river reached 13 metres.
"What we've got at the moment is only a one-in-10-year flood," said SES Director General, Brigadier Philip McNamara.
NSW Premier Bob Carr is expected to visit the area to review rescue measures and any damage.
Flood warnings were also issued for major rivers in northern NSW, including the Tweed, Richmond, Lower Clarence, Brunswick and Bellinger rivers.
At Tweed Heads, authorities said the 382mm of rain that fell in 24 hours was a record.
But the weather bureau said the rain was likely to clear along the northern NSW coast.
The downpour brought hope to many drought-affected areas, but only time will tell whether it's enough.
But in a cruel blow for some, heavy rain washed away some recently planted crops.
6,000 residents of  in  have been told to evacuate their homes.

A couple is missing on the  in Queensland.  State Emergency Services (SES) workers are currently preparing to evacuate a number of nursing homes in the suburbs of  and .

The  (BOM) have said that South East Queensland has recorded rainfalls of 368mm in the last 24 hours and that the Gold Coast suburb of  has been averaging 80mm per hour for at least two hours.  The Coolangatta airport was closed due to flooding.

Further south the city of Lismore has been inundated.  A recently constructed levy has held back the waters of the , protecting the town's central business district.