Sydney residents evacuated from homes overnight as heavy rain brings fresh flood risks

Thousands of residents in Sydney’s south-west were ordered to evacuate overnight as heavy rain swelled rivers, with fresh flood risks for places as far apart as the Illawarra and Kempsey in northern New South Wales.

The State Emergency Service has given evacuation orders for a “substantial” population in about a dozen Sydney suburbs, mostly in the Georges River area. Tens of thousands of people are affected. These include parts of Chipping North, Milperra, Picnic Point and Warwick Farm.

All up, the NSW SES has issued a total of 54 evacuation orders across the state and has 16 warnings out for possible evacuation. The evacuation orders to leave cover an estimated 37,530 people.

The SES conducted 100 flood rescues in the 24 hours to 5am Tuesday morning.

The Bureau of Meteorology issued a warning for damaging winds and heavy rain for a region stretching from near Taree on the mid-north coast almost to the Victorian border in the state’s far south.

The bureau said a low pressure system was expected to deepen and develop into an east coast low near the Hunter coast this morning and track south. It will be the second east coast low in less than a week and may bring more damaging winds than last week’s.

“Heavy rainfall which may lead to flash flooding is forecast for the Mid North Coast, Hunter, Sydney Metropolitan, Illawarra, South Coast, and parts of the Central Tablelands districts,” the bureau said. “Six-hourly rainfall totals between 70mm to 120 mm are possible.”

It added that totals could even reach 150mm during that period if thunderstorms developed.

Importantly given the population centres, the peak of the rainfall would most likely be in the Sydney metropolitan, Illawarra and south coast districts.

The track the east coast low takes before it moves off into the Tasman Sea will be key, since it’s the southern edge of the system that typically cops the worst wind and rain.

Sydney’s 95.4mm of rain to 9am on Tuesday means the harbour city has had the wettest start to any year.

That’s according to the number crunching by Weatherzone’s Ben Domensino. By his reckoning Sydney has had 821.6mm so far in 2022, beating the previous record of 782.2mm in 1956.

Rainfall data at Sydney Observatory Hill go back to 1858.

Domensino says the state’s heaviest rain in the 24 hours to 9am on Tuesday was at Mittagong in the southern highlands, which received 232mm. “This is more than two months’ worth of rain for Mittagong at this time of year,” he said.

Of the overnight evacuations, an SES spokesperson, Shellie Smyth, said: “There was a cell that sort of moved from up north down into Sydney, and it dumped in some cases over 100mm of rain in a very short space of time into an already saturated catchment, which caused rapid river rises. Obviously we had to issue those evacuation orders.”

Among areas outside Sydney facing flood risks on Tuesday were Kempsey and parts of the Illawarra and Shoalhaven areas, Smyth said.

In the period since 9am on Monday, several areas in the Sydney region had collected more than 100mm of rain, including Holsworthy and Bankstown.

Rivers are also at major flood level in several parts of the state, with Sydney’s flood-prone Hawkesbury-Nepean among them.

“Major flooding above the March 2021 event is occurring at some locations along the Upper Nepean, Hawkesbury, and Colo Rivers,” the bureau said. “Forecast rainfall for Tuesday may cause further renewed rises.”

Warragamba Dam, which has been flooding since 3am on Wednesday, is continuing to spill, with the rate quickening again overnight, bureau data showed.

As of Tuesday morning, authorities were predicting the dam’s peak spill rate could reach as much as 400 gigalitres a day, or not far from the March 2021 peak of 440GL a day. Last week’s peak was 315 GL a day. Inflows into Lake Burragorang behind the dam had risen to 300GL a day, the government said.

Along with the rain, there is damaging surf along much of the central NSW coast, and also the risk of damaging wind gusts that could bring down trees. Landslips are also a risk and motorists are advised to take care – if they have to be out on the roads at all in areas where the weather is particularly fierce.

Those winds could reach peak gusts in excess of 90km/h in the Sydney metropolitan, south coast, Illawarra and southern tablelands districts, including the Australian Capital Territory ranges, the bureau said. “The risk of damaging wind gusts is expected to persist into Wednesday.”