Thousands of people were advised to evacuate Sydney’s outskirts on Sunday after Australia’s east coast was hit by record rainfall and extensive flooding.

A day after officials warned of potentially “life-threatening” flash floods in New South Wales, emergency services issued evacuation orders for several low-lying areas in the city’s north-west.

As torrential rains pummelling a vast coastal area already soaked by an unusually wet summer on Saturday, people began clamoring to evacuation centers in cities north of Sydney.

In Taree, where photos of television showed that a house floated down a river, around 150 people slept overnight in a local auditorium which used to hide people fleeing bushfires.

The floods were described as a “catastrophe” by Club Taree CEO Paul Allen, who told public broadcaster ABC that some residents had “lost everything.

The heavy rains were expected to move down the coast over the weekend, with the wild weather expected to last until Thursday.

The Warragamba Dam, which supplies much of Sydney’s drinking water, spilled over Saturday afternoon, in what specialists predicted to be the reservoir’s first major overflow since 1990.

Overnight Saturday and Sunday, emergency services received over 1,000 calls for assistance and performed about 100 flood rescues.

According to sources, authorities have said that an approx 4,000 residents may be ordered to leave their homes in the coming days. Gladys Berejiklian, Premier of New South Wales, has stated that the state is experiencing a “deep-seated, extreme weather event” that could last for several days. “I hate to say it again to all of our state residents, but it’s not going to be an easy week for us,” she said in a televised briefing.

Experts say that the rains will continue unabated in the coming days, with the region receiving up to 1,000mm more rain. The bureau of meteorology has also predicted that rain and floods will return to North Sydney on Monday, but will subside later in the week.

The rain and flooding were expected to postpone the already stalled roll-out of coronavirus vaccines in Sydney and surrounding areas.

The nation is set to commence the first major public phase of vaccine distribution on Monday, despite the fact that the program has fallen behind the government’s announced timeline due to supply and delivery problems.