Authorities in the Australian city of Sydney on Sunday ordered thousands of people to evacuate their homes after torrential rain hit the outskirts.
Roads were closed and at least 18 evacuation orders were issued in the west of the city, an area hit by severe flooding in March.
“This is a life-threatening emergency,” warned Stephanie Cooke, Minister for Emergency Services in New South Wales, whose capital is Sydney.
Australia is particularly hard hit by climate change, with regular droughts, devastating forest fires and recurring and increasingly severe floods.
With more bad weather expected in the coming days, Ms Cooke described a “rapidly evolving situation” and warned that people “should be prepared to evacuate places urgently”.
The Warragamba Dam began to overflow in the early hours of Sunday, she said, well ahead of authorities’ forecasts.
Shops and a gas station have already been flooded in Camden, a suburb southwest of Sydney with more than 100,000 residents.
Emergency services rescued 29 people and were called more than 1,400 times in the past 24 hours.
In March, severe storm floods devastated western Sydney, killing 20 people.
As the world warms, the atmosphere will hold more water vapor, increasing the risk of flooding and heavy rain events, scientists say. This precipitation, along with other factors such as land use planning, can lead to flooding.