BRISBANE, Australia (AP) - Tens of thousands of people had been ordered to evacuate their homes by Tuesday and many more had been told to prepare to flee as parts of Australia’s southeast coast are inundated by the worst flooding in more than a decade that has claimed at least 10 lives.

Scores of residents, some with pets, spent hours trapped on their roofs in recent days by a fast-rising river in the town of Lismore in northern New South Wales state.

The body of a woman in her 80s was found by a neighbor in her Lismore home on Tuesday, a police statement said. There were no details of how she died.

There were concerns that householders who climbed into their roof spaces through ceiling manholes could become trapped by rising waters.

A police rescue officer had saved an elderly woman from such a roof space that was almost filled with water, Lismore State Emergency Service Commander Steve Patterson said.

“He dived in through a window, noticed the manhole cover was open, when he checked, found a 93-year-old lady with about 8 inches left of space before the water hit the top,” Patterson said.

Dozens of cars were trapped on a bridge in the nearby town of Woodburn over Monday night with both the bridge’s approaches submerged.

Up to 50 people were rescued from the bridge early Tuesday, officials said.

“We had no capabilities to get them off in the dark so we just had to make sure that they bunkered down and we went in this morning and got them all out,” Woodburn State Emergency Services Commander Ashley Slapp said.

The floodwaters are moving south into New South Wales from Queensland state in the worst disaster in the region since what was described as a once-in-a-century event in 2011.

New South Wales Premier Dominic Perrottet said there had been 1,000 rescues in his state by Tuesday and more than 6,000 calls for authorities to help.

Perrottet said 40,000 people had been ordered to evacuate, while 300,000 others had been placed under evacuation warnings.

“We’ll be doing everything ... we can to get everybody to safety and get these communities right across our state back on their feet as quickly as possible,” Perrottet said.

Government meteorologist Jonathan Howe described the amount of recent rainfall in northern New South Wales and southern Queensland as “astronomical.”

Nine of the 10 deaths reported so far were in Queensland. A 76-year-old man who disappeared with his vehicle in floodwater northwest of Brisbane on Sunday has since been confirmed dead.

Queensland Police Commissioner Katarina Carroll said emergency services held grave concerns for another man in his 70s who fell from his moored yacht in the state capital Brisbane into a swollen river on Saturday.

The cleanup was underway in Australia’s third most populous city, despite more storms in the forecast for later in the week, with Brisbane Lord Mayor Adrian Schrinner urging people to register for the “Mud Army,” as the thousands of volunteers who mobilized to help out after the 2011 floods were dubbed.

Thousands of homes in Brisbane were inundated Sunday, many by destructive surges in swollen creeks in suburbs such as Ashgrove, where Kelvin Barfoot had to evacuate with members of his family, including his 99-year-old mother-in-law, Mina Baker, in a State Emergency Service rescue boat.

In a social media posted with the hashtag #Rainbomb, Schrinner said the national weather agency had confirmed the six-day total rainfall for downtown Brisbane - 31.2 inches to Monday morning - was significantly higher than the previous record of 25.8 inches set when flooding devastated the city in 1974.

The extraordinary rainfall comes as the United Nation’s Intergovernmental Panel on Climate Change reported this week that vast swathes of Australia have already lost 20% of its rainfall and the country’s fire risk has gone beyond worst-case scenarios developed just a few years ago.

Australia’s hottest and driest year on record was 2019 which ended with devastating wildfires across southeast Australia.