NSW flooding: Sydney's Warragamba Dam overflows and mid north coast evacuated amid wild weather

Swathes of suburban Sydney were on alert for dangerous flooding after the city’s main dam spilled over on Saturday, with severe storms across New South Wales also triggering a mini-tornado, evacuations, and hampering coronavirus vaccine delivery.

Warragamba Dam spilled over at about 3pm on Saturday and daily rainfall records for parts of the mid north coast for March were broken by more than 100mm.

As a result of the dam spilling over, the Bureau of Meteorology issued warnings for major flooding across western Sydney, including at Penrith, North Richmond, Wallacia and Sackville – areas where there had been a surge in urban development.

Water scientists were not sure how the increase in pavement and hard surfaces would affect the increased river flows, as much of the area was mostly bush when the dam most recently substantially spilled over in 1990.

Separately, more than 30 homes were damaged in Chester Hill, in Sydney’s west, and one thousand residents left without power following a mini-tornado that formed due to intense local rainfall and strong rotating winds.

Saturday’s wild weather occurred in areas marked by droughts and bushfires in recent years, with Sydney’s water levels dropping so low in 2019 that water restrictions were triggered, while Port Macquarie, Taree and areas of the north coast experienced the early brunt of the Black Summer bushfires.

NSW’s State Emergency Service had carried out 500 flood rescues and responded to 4,000 calls for assistance by Saturday afternoon, with the state’s emergency services minister, David Elliott, urging residents to obey pleas not to drive into flood waters and force volunteer rescuers to risk their lives responding to a callout.

“Five hundred flood rescues over the course of this operation so far is just completely unacceptable,” Elliott said.

The Pacific Highway and other main roads were closed on Saturday, with images emerging of flood waters rising above bridges and roads crumbling, while a home in Taree was seen floating off its foundations down the Manning River.

The premier, Gladys Berejiklian, told residents to be on high alert and be ready to leave their homes on the mid north coast, the Hunter, the Central Coast, metropolitan Sydney and the Warragamba Dam catchment area.

Berejiklian warned the “deep-seated, extreme weather event” could last until the end of next week for some parts of the state, amid a prediction from the BoM that rainfall totals of one metre were possible over that period.

“It’s not going to be an easy week for us,” Berejiklian said.

Evacuation orders were issued for low-lying property across areas including Port Macquarie, Kempsey, Taree and Macksville on Saturday, with evacuation centres set up to house those forced to flee.

On Saturday afternoon, the Department of Health warned the extreme weather and flooding was so severe that “vaccine delivery is being affected in Sydney and across multiple regional NSW locations”.

A spokeswoman said the department was “working directly with GPs on these issues and we ask for the public’s patience and understanding with these unforeseen supply delays”.

In Taree, surging flood waters lifted a house from its foundations, and it was filmed moving at speed down the river, which was expected to peak at 5.8 metres later in the day.

Lyle Edge said his brother lived in the house with his partner. They should have been getting married on Saturday. Instead they had been left homeless and their pets were dead.

Dr Ian Wright, a water scientist at Western Sydney University who previously worked as a scientist for Sydney Water studying the Sydney basin flows, said it was unclear what the impact of development and more hard surfaces would have on the floodplain after flows from Warragamba Dam join other rivers.

He warned that large swathes of western Sydney that were previously bushland and soil – which absorb water before flooding – had been paved over and roads and hard surfaces built to support new suburbs in recent years, and that many of these suburbs “are pretty close to the floodplain”.

“It’s going to be a long night for everyone. We are absolutely in uncharted territory,” Wright told the Guardian.

“Because of all the hard surfaces that have popped up, we don’t know how the hydrology will react,” he said.

The senior BoM climatologist, Agata Imielska, said greater Sydney could expect about 100mm of rain during the next 24 hours or so, but the lower Blue Mountains was expected to get 200-300mm.

The rain band was moving down from the Kimberley and would reach eastern NSW from Monday night, when it would “link up” with the slow-moving coastal trough that was causing the flooding in NSW.

“That’s when we’ll see a very large burst of rain, across eastern NSW, dipping into north-eastern Victoria and south-east Queensland from Monday night into Tuesday,” meteorologist Jonathan How said.

A severe weather warning issued by the BoM on Saturday stretched from the mid north coast to the far south coast of NSW as well as Canberra.

Taree CBD copping it. And yes, that’s the roof of a car. @nbnnews pic.twitter.com/pRdBa2ebwF

Martin Bridge has now been closed to traffic. Manning River expected to peak at 3pm. @nbnnews pic.twitter.com/OnH1kboTg5

Outside Sydney, there was likely damage to property in several coastal towns, including Port Macquarie, where flooding had hit the city centre, Taree, where images showed a house floating down the Manning River, and Kendall, which was also inundated.

About 17,000 residents were covered by evacuation areas including the low-lying areas of Port Macquarie, Taree, Kempsey and Wauchope.

Mum and Dad are in the town centre of #PortMacquarie looking onto the canals which feed into the Hastings River. Several jetties have come adrift and a cow has been spotted in someone’s front yard | @abcnews @kerrinjthomas @Hannah_Palmer @portmacnews @BOM_NSW @BOM_au #NSWFloods pic.twitter.com/8EzGeAtqN7

Major flood warnings were in place for at least five waterways, including the Hastings and Gloucester rivers.

There was major flooding along the Hastings River at Kindee Bridge, Wauchope and Settlement Point.

The Hastings River at Kindee Bridge peaked at 12.1 metres about 11pm on Friday and was at 9.87 metres and falling with major flooding on Saturday.

The Hastings River at Wauchope was at 8.5 metres and near its peak with major flooding on Saturday.

The Hastings River at Settlement Point was likely to peak near 2.1 metres on Saturday with major flooding.

Major flooding also hit Macksville and Bowraville overnight.

Short Street Port Macquarie #NSWFloods pic.twitter.com/wXMQbUn17q

Residents of low-lying areas of Port Macquarie were told to evacuate on Friday, amid expectations a “significant” number of properties would be inundated.

Nearby areas of North Haven, Dunbogan, Camden Head and Laurieton were also ordered to leave, as well as those living in Kempsey and along the lower Macleay River.

Michael Ward, the NSW SES Port Macquarie unit commander, said Coffs Harbour had also been hit, though “not quite as hard as they were expecting”. “However, they have had evacuations up there,” he said.

Ward warned people who had been left isolated by flooding that it might take 12 to 18 hours before they could be rescued.

“If you are isolated, you need to isolate and shelter in place,” he said. “We will get to everyone, however, it is delayed.

“We’ve been pulling too many people out of cars, off cars, out of caravans where they’ve tried to drive through flood water and have been trapped.”

Emergency services warned road and surf conditions would remain dangerous and were telling motorists and boaties to stay home.

⚠️ MAJOR #Flooding possible #Hawkesbury #Nepean and #Colo Rivers at North #Richmond #Windsor and #Sackville Moderate flooding at #Menangle, #Wallacia #Penrith #Portland #WisemansFerry. See https://t.co/T2T8tzpPE7 for details and updates; follow advice from @NSWSES. #NSWFloods pic.twitter.com/ax4jykVKio

The deluge was set to continue well into next week and could deliver the heaviest rainfall since February 2020, when greater Sydney was hit.

Woolloomooloo for you #3 pic.twitter.com/gIZVridJH5

The BoM said rainfall totals to 9am on Saturday had reached 406mm at Delward, 371mm at Redoak and 362mm at Logans Crossing, smashing previous March records.

Australian Associated Press contributed to this report