Extreme rainfall on the east coast of Australia beginning on 18 March 2021 led to widespread flooding in New South Wales, affecting regions from the North Coast to the Sydney metropolitan area in the south. Suburbs of Sydney experienced the worst flooding in 60 years, and the events were described by NSW Premier Gladys Berejiklian as "one in 100-year" flooding. Far-southeast communities in Queensland were also affected by flooding and heavy rainfall, though to a lesser extent than those in New South Wales.
The Australian government declared many parts of the east coast a natural disaster zone after the flooding rains forced 18,000 people to evacuate, in addition to over 1,000 flood rescues.House floats downriver in Wingham as dangerous weather system leaves a path of destruction by ABC News. 20 March 2021 Described as a "prolonged event" by Berejiklian and "dangerous and threatening" by the Bureau of Meteorology, the floods extended from the coastal towns of Taree and Kempsey on Thursday, 18 March, to the populated suburbs of western Sydney by Friday and Saturday.Parts of Australia declare natural disaster during 'once in 100 years' floods by Jessie Yeung from CNN. 21 March 2021
The floods occurred less than 18 months after Australia was affected by the Black Summer bushfires, impacting many towns still recovering from the previous disaster.NSW flooding: disaster zones declared as 18,000 people evacuated in Sydney and mid-north coast by Michael McGowan and Justine Landis-Hanley from The Guardian. 22 March 2021
Background
Weather Persistent, heavy rain fell from March 16 to March 23 in New South Wales. The Bureau of Meteorology reported that areas around Sydney and the Hunter Valley were drenched with more than to of rain in this time period. This region only receives an average of about to of rain in a year.
The storm brought record rainfall in the north coast, with towns near Port Macquarie, such as Kendall, seeing record rainfall of more than between 19 and 20 March.Record rains, flooding prompt evacuations in Australia by Yahoo! News According to the Bureau of Meteorology, in an event described as "volatile, dangerous and dynamic", the heavy rainfall event was caused by a blocking high in the Tasman Sea (between Tasmania and New Zealand) that directed a strong, low pressure trough towards the NSW coast.Widespread rain to fall in all states as two storms form in Australia's east and west by Ben Deacon from ABC News. 20 March 2021 The floods occurred due to the arrival of the La Nina weather pattern in September 2020, with the floods being La Nina's final storm event as the Bureau of Meteorology declared the phenomenon over on March 30.La Nina’s final fury The Sydney Morning Herald. Retrieved 3 December 2020.
Flooding The state was not evacuated because of the floods. New South Wales State Emergency Service (SES) had responded to over 12,000 requests for help and 1000 direct flood rescues since 18 March during the storm, with the coastal area between the Mid North Coast and Greater Sydney being the most affected by the storm, where the SES had given flood evacuation warnings in many areas of these regions.NSW weather live: NSW Premier Gladys Berejiklian warns of 'prolonged 'event by ABC News. 20 March 2021
Across the state, 10,000 people have been affected by evacuation orders, though around 18,000 people have been evacuated from their homes (3,000 of those in Western Sydney and about 15,000 in the Mid North Coast), Many evacuation centres have been set-up to accommodate the displaced residents, in addition to over 130 school closures and road closures, which were cut off by water. Since 20 March, after the torrential rain began, around 450 gigalitres of water a day had been released from the Warragamba Dam, equal to the contents of Sydney Harbour, which is around 500 gigalitres.
The NSW and Australian governments had declared 16 natural disaster zones in areas from the central and mid-north coast, from Hunter Valley near Sydney, to Coffs Harbour, with the SES responding to 7,000 calls for assistance throughout the eastern seaboard.NSW flooding forces 2,000 people to evacuate, schools closed, workers told to stay home by ABC News. 22 March 2021 Major flooding occurred along the Hawkesbury River, the Macleay River, the Wollombi Brook, Rickabys Creek, Widemere Detention Basin, Manning River and the Colo River.
Deaths and disappearances Fatalities include one elderly man who lost control of his vehicle in heavy rain, colliding into a tree in Mona Vale, and a bodyboarder in his 60s who disappeared on the Coffs Harbour seashore and is presumed to be dead. On 24 March, two more fatalities were confirmed; In Glenorie, the body of a 25-year-old man was found trapped in a car approximately 6 metres (20 feet) underwater, whilst in Canungra, the body of a 38-year-old was found in an overturned ute in rapid floodwaters. An elderly woman was missing since March 26 after her car was found submerged in the waters. Her body was later recovered.
Extent Gold Coast and Logan Area
This region, including nearby Logan and Scenic Rim catchments recorded over of rain in just a few hours in the late night of 22 March 2021.South East communities ravaged by 'intense' flash flooding as storm emergency continues by 9NEWS. 23 March 2021. This led to major flooding of both the Logan and Albert Rivers, where on the next day, with Gold Coast City Council announcing an evacuation notice to all residents on two of its roads, Crest Hill Drive and nearby Lanes Road in the suburb of Wongawallan.Gold Coast Homes Evacuated due to Landslip Amid Warning by 7 News Queensland. 23 March 2021. Nearby 8-hour rainfall totals on 22 March 2021 include Carbrook with and Springbrook with .Drenching for another day as Premier pleads for drivers to stay home by Brisbane Times. 22 March 2021.
Mid North Coast In parts of this region, more than of rain had fallen in just two days causing lowland areas to flood and be reminiscent of inland seas. In Taree, a house was found drifting on the Manning River after heavy rainfall caused by this nor'easter. Additionally, many evacuations were ordered throughout the region, including Kempsey, Wingham, Dumaresq Island, Cundletown, Laurieton, Nambucca Heads, North Haven, Dunbogan, Bulahdelah, Kings Point, Macksville and the low-lying areas of Wauchope, Rawdon Island, Lower Macleay and Port Macquarie. Some towns in this region had received of rain since 18 March, including Comboyne which has registered . The Manning River in Taree would end up swelling to 5.65 metres at its peak, falling just short of the record high of 6.0 metres set in 1929. As a result of debris being carried downstream, the Martin Bridge was closed off due to concerns of its structural integrity after being hammered with hay bales, shipping containers and other machinery.
All Qantas flights in Port Macquarie were cancelled after the airport was cut off by flooding roads. Around 5,500 customers in this region were without power.House floats down river in Wingham as dangerous weather system leaves a path of destruction by ABC News. 20 March 2021 Furthermore, supermarkets were virtually emptied due to panic buying, with Woolworths in Lakewood being cleared of bread, eggs, meat and vegetables, reminiscent of the COVID-19 lockdowns a year ago, after residents were told to evacuate in nearby North Haven, Laurieton, Dunbogan and Diamond Head.Not again! Panic buying hits flood areas with supermarket shelves cleared of bread, vegetables by The World News. 22 March 2021.
Hunter Valley On Saturday 20 March until Wednesday 24 March, flights from and to Newcastle Airport were suspended due to flooding of the airfield. A number of roads in Newcastle, Lake Macquarie, Port Stephens, Cessnock and Maitland were closed due to them being overflowed by floods.Newcastle and Hunter road closures, hazards and flooding | Monday 22 March by the Newcastle Herald 22 March 2021. Though overall, the Hunter region has mostly been spared from the predicted severity of the storm, with the Mid North Coast being the most devastated.Saturday weather update: Paterson, Williams peak, Mid North Coast cops the worst of severe weather by The Newcastle Herald. 22 March 2021.
Sydney
On 20 March, a tornado damaged homes and toppled trees in Chester Hill, a western suburb of Sydney, leaving thousands without electricity.NSW weather: mini-tornado damages homes in Chester Hill, says NSW Premier Gladys Berejiklian by ABC News. 20 March 2021 Heavy rain flooded the site of Parramatta Powerhouse and as well as the Parramatta ferry wharf, which was overflowed after Parramatta River broke its banks.Parramatta River breaks its banks, flooding Powerhouse Museum site by Linda Morris and Andrew Taylor from Sydney Morning Herald. 21 March 2021 The Warragamba Dam began to spill, which was the first significant overflow of the reservoir since 1990. Because of rising floodwaters, which were not seen since the November 1961 floods, Nepean River and Hawkesbury River were overflowed, peaking at , with Windsor Bridge becoming submerged, leading to inundated homes and isolated animals.
Some areas within the suburbs of Jamisontown, Mulgoa, North Richmond, Hawkesbury Valley around Agnes Banks, Freemans Reach, Cornwallis, Pittown North, Richmond, Windsor and Penrith were submerged after the rivers burst their banks.Residents in Sydney's north-west told to prepare for evacuations by Freya Noble from 9 News. 22 March 2021. Over 2,000 people living in or proximate to those suburbs were evacuated, in addition to many homes and farmlands being inundated therein. Residents within the Warragamba Dam catchment area were on high alert on 21 March after the city's main water source had reached its volume with the communities of North Richmond, Wallacia and Sackville being at most risk. Volunteers filled sandbags for the residents there to protect their homes.
The dam had received more than of rain between the 20th and 21st, and more than until 22 March. Sydney CBD received of rain on the 20th, whereas Hornsby had gotten and Picton and Oakdale had , with some areas receiving four times more rain in two days than the entire March monthly average.Sydney weather live: Evacuation warnings across Western Sydney and Mid-North Coast as Warragamba Dam overflows by ABC News. 21 March 2021
Response
Australian Prime Minister Scott Morrison said, "Australia is being tested once again", before addressing, "the terrible storms and floods that have been ravaging NSW for the past few days are taking a heavy toll", where he mentioned that he has been in regular contact with Berejiklian. Morrison had praised emergency workers and volunteers, where he encouraged people in the disaster zones regions to heed the advices and warnings, stating, "for now, our message is very clear to keep yourself safe, to keep your family safe and those around you to follow the instructions of the very competent, professional agencies and bodies and the volunteers who support them."
Premier Berejiklian stated, "I don't know any time in the state's history where we have had these extreme weather conditions in such quick succession [and] in the middle of a pandemic."
Climate Council spokesperson Professor Will Steffan stated that intense rainfall and flood events are occurring more frequently due to climate change.
European Commission's European External Action Service activated the Copernicus Emergency Management Service – Mapping in order to produce delineation and damage grading maps of floods in the Beaudesert, Bulahdelah, Grafton, Greater Port Macquarie, Kempsey, Laurieton, Maitland, Moree, Tamworth, Taree, Western Sydney and Wisemans Ferry areas of interest.
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