The entire NSW coast from Tweed Heads to the Victorian border has been warned to brace for damaging winds, heavy rainfall and wild surf as a weather system that has brought the worst flooding in decades continues to expand.
The Bureau of Meteorology said around 10 million Australians in every mainland state and territory except Western Australia were subject to the weather warning — “an area similar to the size of Alaska”, the largest state in the United States.
The NSW SES received 1485 requests for assistance in the 24 hours to Monday night and completed 125 flood rescues including 70 in Sydney, predominantly around the Hawkesbury area.
The Australian Defence Force will also support NSW’s flood emergency efforts from Tuesday, with two search and rescue helicopters operating out of the South Coast in 24-hour operations.
There were 540 SES teams in the field on Monday — more than 1750 volunteers — and the service was “gearing up teams in the south, from Wollongong through to the border”, a spokeswoman said.
In NSW, the inland trough stretching the continent was poised to collide with the coastal trough that has brought heavy rain to the eastern part of the state over the past five days.
The north-west was saturated on Monday, with Moree, Dubbo, Armidale, Tamworth and the Central West slopes affected, and the weather system was expected to extend to the ACT, South Coast, Snowy Mountains and Northern Tablelands.
In a bid to fast-track the processing of claims, the Insurance Council of Australia declared an insurance catastrophe after more than 5000 claims were lodged over the weekend. Analysts said premiums were likely to rise.
Prime Minister Scott Morrison said the situation is “evolving and is extremely dangerous”.
“This will be a very difficult week for hundreds of thousands of Australians,” he said.
The bureau warned residents of the South Coast to expect 200 to 300 millimetres of rain in the coming days, with an ensuing flood risk.
The Upper McIntyre, Gwydir and Namoi Rivers in the north were likely to experience moderate to major flooding.
NSW SES volunteers in Nowra and Shoalhaven spent the day sandbagging and removing trees in preparation for anticipated floods. Shoalhaven councillor Bob Proudfoot said St Georges Basin near Jervis Bay typically backed up and inundated low-lying properties, along with Lake Tabourie, Burrill Lake and Lake Conjola.
“Over the years we’ve built up a levy bank along the Shoalhaven River to such an extent that we would like to think we’re safe, but that could overflow as well,” Mr Proudfoot said.
A wall of water that spilled from Warragamba Dam on the weekend had passed western Penrith and Jamisontown by early Monday afternoon, but the Hawkesbury-Nepean River was still rising downstream at North Richmond, Windsor, Pitt Town and Wisemans Ferry as water poured into the river system from across the catchment.
A father and son were trapped on the upper storey of their house on Old Pitt Town Road and had to be rescued by SES volunteers in a rubber dinghy.
The Colo River, which drains the northern section of the Blue Mountains, gathered pace as it moved towards the Hawkesbury River, bulging its banks and rising to 14.8 metres hours ahead of its anticipated peak and causing major flooding at the Upper Colo and Putty Road Bridge.
Bureau of Meteorology flood forecaster Justin Robinson said it was the worst flooding he had experienced in his 20-year career. River levels at Penrith peaked higher than they did in 1961. At Windsor, they were expected to exceed the levels they reached in 1988. And the rain continued to inundate the catchment.
Water NSW said the spill rate at Warragamba Dam reached 500 gigalitres a day on Sunday, slowed to 300 gigalitres on Monday and was expected a hit a second peak of around 400 gigalitres a day by midweek.
By evening, residents of the Widemere Detention Basin in Greystanes and parts of Wetherill Park were asked to evacuate.
The north copped the brunt of rainfall, with 245 millimetres of rain at Nambucca Heads, 183 millimetres at Coffs Harbour and 182 millimetres at Woolgoolga. An elderly woman who broke her hip was rescued by SES volunteers and motored across the river to a waiting ambulance in Kempsey.
Flooding delayed the COVID-19 vaccination rollout, with delivery to about 50 clinics blocked by floods, while others were forced to close or had patients unable to attend their appointments.
On Monday night the bureau said “unfortunately this situation is far from over”, adding that “more rain was forecast for the coming days”.
At 11pm its severe weather warning said heavy rain would continue in the state’s east and across the northern inland for the rest of the night and on Tuesday.
“As the trough reaches the Tasman Sea by late Tuesday, a low pressure system may form off the South Coast, bringing increased rainfall to the south and east, together with strong winds, damaging surf and abnormally high tides along the coast,” it said.
The bureau’s NSW/ACT manager of weather services Jane Golding said the worst of the weather would be over for Sydney by Tuesday evening. “We might see some stars tomorrow night,” she said.
Start your day informed
Our Morning Edition newsletter is a curated guide to the most important and interesting stories, analysis and insights. Sign up here.
Harriet Alexander is a reporter for the Herald.
Breaking News Reporter
Laura is a crime reporter for The Sydney Morning Herald.