Sydney has been lashed by one of its heaviest short-duration downpours in recent memory, with some parts of the city recording 100mm of rain in just a few hours. The deluge triggered flash flooding across the metropolitan area, prompted dozens of emergency rescues, and has now raised concerns about shark activity at beaches and river mouths across the New South Wales coast.
The NSW State Emergency Service fielded more than 490 calls for assistance during the event, according to 9News. Of those, 42 resulted in swiftwater rescues. Residents in Fairfield East were among those evacuated as stormwater inundated local streets, and vehicles were submerged in shopping centre carparks across the city's west. Roads were cut throughout the metropolitan area as waterways burst their banks.
With the rain clearing through the morning, the Bureau of Meteorology cancelled its severe weather warning for Greater Sydney. Flood warnings, however, remain active across much of outback NSW, Queensland, South Australia, and the Northern Territory, driven by a near-stationary tropical low system sitting over Central Australia and slowly pushing south.
In the wake of the flooding, NSW SharkSmart issued a public warning urging swimmers and beachgoers to exercise caution. The agency noted that heavy rainfall rapidly alters beach and waterway conditions, with freshwater run-off reducing underwater visibility and nutrient-rich sediment attracting baitfish, which in turn draws sharks closer to shore and into river systems.
"Heavy rain can change beach and waterway conditions quickly. Freshwater and nutrient-rich run-off can reduce visibility, affecting water quality and attract baitfish, sometimes increasing shark activity." — NSW SharkSmart
Swimmers are being advised to avoid murky or discoloured water entirely, to stay well clear of river mouths and harbour entrances within a one-kilometre radius, and to watch for signs of baitfish activity, diving seabirds, and dolphins, all of which can indicate predatory sharks are nearby. The warning follows a troubling period on the NSW coast, during which a series of storms coincided with a cluster of shark attacks. One incident at Vaucluse resulted in the death of a young boy after he was attacked by what experts believed was a bull shark. Authorities at the time noted that storm conditions can provide cover for bull sharks and draw them into shallower, nearshore environments.
Adelaide braces for its turn
Attention is now turning to South Australia, where Adelaide is forecast to receive more than 100mm of rainfall in the coming hours. Several events in the city have already been cancelled in anticipation of flash flooding across the metropolitan area. The same slow-moving tropical low driving the Sydney event is responsible, its moisture-laden system feeding rain into four states simultaneously.
Outback Queensland has also seen extraordinary rainfall totals. The remote town of Birdsville, situated roughly 10 kilometres from the South Australian border, recorded 93.2mm in the 24 hours to 9am on Thursday, according to Weatherzone. That single-day total represents more than half of Birdsville's annual average rainfall of 161.4mm and placed the town second on Queensland's 24-hour rainfall rankings for that period, behind only Fall Creek on the far more tropical Cape York Peninsula.
Events like this one are a reminder of how quickly Australia's climate can swing between extremes, and how the costs of inadequate urban flood infrastructure are borne most heavily by ordinary households and local emergency services. The SES, which relies substantially on volunteers, managed hundreds of calls over a compressed period, a pressure that recurs with increasing regularity. Whether governments at all levels are investing sufficiently in both flood mitigation and community resilience remains a fair and pressing question, even as the immediate focus rightly stays on those still dealing with the aftermath.