Sydney floods: Warnings of further deluge as major dam spills

Flood waters are expected to rise in Sydney after torrential rainfall on Friday caused flash flooding in parts of Australia's second-largest city, the authorities have warned.

Heavy rain pummelled parts of the city for 24 hours, forcing thousands to evacuate the city's outskirts.

The rain also caused the city's main supply of water, the Warragamba Dam, to spill two days earlier than expected.

People living downstream of the dam have been warned to expect more floods.

The dam started spilling on Saturday morning and has been pumping the equivalent of 80,000 Olympic-sized swimming pools downstream every single hour since, according to the Sydney Morning Herald.

The dam's water levels were expected to peak by midnight local time (13:00 GMT) on Saturday, according to officials. But some residents have been warned of further flood risks as most of the water from the dam is yet to reach Sydney's flood-prone areas.

"We have been out with the community, letting them know what is coming and ensuring they prepare," New South Wales State Emergency Service commissioner Carlene York told reporters.

"We don't think those waters are affecting a significant amount of people in those areas but certainly rural farmland, stock and families and businesses... need to be aware of the next couple of days as the water will continue to flow down at a high level in those river systems."

The water levels in the Hawkesbury and Nepean rivers are expected to rise in the coming days.

WaterNSW CEO Andrew George said there was also water spillage coming from other dams, including the Tallowa Dam on the Shaolhaven River and the Blue Mountains dam. Spillages from three other metropolitan dams was expected, he said, quoted by 9News.

The storm led to a month's worth of rain pummelling Sydney on Friday, leading authorities to issue emergency evacuation warnings for many of the city's low-lying areas, including Richmond and Windsor.

"While it looks like blue skies across Sydney at the moment and the emergency rain situation seems to be easing… it is important to note that flood levels in some of the rivers, particularly in western Sydney, are continuing to rise and that presents a danger for some communities," New South Wales Premier Chris Minns told reporters on Saturday.

More than 150 people were rescued from floods on Saturday, the New South Wales State Emergency Service said, adding that 72 rescues took place in Sydney.

One man was found dead in water near a reserve in Penrith, in Sydney's west on Saturday. New South Wales police said it was not clear whether his death was related to the storm.

Thousands have been left without power.

Many train services across Sydney have not been running because of flooding on the tracks while many roads have also been closed.

The only access road to Megalong Valley in the Blue Mountains, west of Sydney, has been cut off by a major landslide caused by the wet weather.

Local Mayor Mark Greenhill said food drops might have to be organised for residents who were isolated.

"The destruction is so great that we can't even get people out, let alone vehicles," he told ABC Radio Sydney.

Pictures also show houses destroyed in Wollongong city, south of the state capital.

Flood warnings have been issued in Queensland state too, with residents advised to avoid unnecessary travel.

Part of a house washed up in Mount Kiera, Wollongong, south of Sydney