Torrential rain for several days from Friday 7 February 2020 caused flooding on numerous rivers in eastern New South Wales (NSW) and south-east Queensland, with significant disruptions to road and rail traffic. In NSW, major flooding occurred on the Orara, Hawkesbury-Nepean and Georges Rivers, with the Hawkesbury River at North Richmond reaching its highest level since 1992.
The heavy rains were accompanied by strong winds and rough seas. Several people were injured when winds brought down trees and powerlines, which also caused thousands of homes to be temporarily without power. Flash flooding occurred in some areas, and waves more than five metres high lashed the coast, causing significant beach erosion. Up to 25 metres of beach at Collaroy and Narrabeen was swept away by the huge waves.
As river levels rose on 9 February, the NSW State Emergency Service (SES) issued evacuation orders for towns along the Hawkesbury River, as well as Moorebank, Chipping Norton and Milperra along the Georges River on 11 February.
On Monday 10 February, energy distribution crews continued to deal with thousands of hazards, including fallen trees and powerlines, damaged wires and extensive flash flooding. Electricity distributors Ausgrid and Endeavour Energy reported that more than 100,000 customers had lost electricity across Sydney, the Central Coast the Blue Mountains Newcastle and the Southern Highlands.
During of this event, among the largest NSW SES has dealt with, they received 15,680 requests for assistance, most in the Sydney Basin with northern NSW also significantly impacted. The majority of assistance related to leaking roofs, fallen trees and flooded roads. The SES had 379 flood rescue activations, with the majority in the Sydney Metropolitan area. This event was among the largest that NSW SES has dealt with. Fire and Rescue NSW received 16,000 calls for help, many of them flood-related, between 8am Saturday and 8am Monday, a record number of calls over a 48-hour period.
Sydney received 391.6 millimetres (mm) of rain between 7 and 10 February, more than three times the average rainfall for the month and the city’s wettest period since 1990. Other areas of the state also experienced torrential rain; in a 24 hour period covering 9 - 10 February, several locations along the central and southern coast recorded more than 350mm of rain.
The rainfall had a marked effect on Greater Sydney’s water supplies, with major dam levels at 64.2% by 10 February, up from 41.9% in seven days. The Warragamba Dam, which can hold 80% of Sydney’s water storage, received a year’s worth of water in just one weekend, rising 17.7 percentage points to 60.7% by Monday 10 February. An estimated 360,000 megalitres of water had been added, almost as much as 150,000 Olympic-size swimming pools.
On that day, the NSW Rural Fire Service announced that the Gospers Mountain, Myall Creek Road, Erskine Creek, Kerry Ridge, Green Wattle Creek, Morton and Currrowan bushfires, which had been burning for several weeks, had been finally extinguished by the rains. By 13 February, several bushfires that were still burning in parts of southern NSW were also declared under control.
On that day too, the Insurance Council of Australia (ICA) declared the storms and associated flooding a catastrophe, enabling insurance claims to be processed more rapidly. On 28 May, the ICA reported that 96,594 claims for homes and businesses damaged by the rain and floods had been lodged in NSW and south-east QLD, with estimated combined insurance losses of $896 million. Most claims were for property damage caused by storm runoff, flooding, strong winds and heavy rain.