Sydney has seen its heaviest rain in 30 years, leading to flooding, travel chaos and forcing thousands of Australians from their homes.
Australia's Bureau of Meteorology (BoM) said 391.6mm of rain had fallen in the past four days, and warned of potentially life-threatening flash floods.
The rainfall has left about 100,000 homes without power.
The rains are a welcome relief by also putting out many of the bushfires which have torn through the state of New South Wales in recent months.
One fire now extinguished by the rain from the severe thunderstorms is the Currowan fire, which had burned for 74 days around the town of Shoalhaven, destroying nearly 500,000 hectares of land and 312 homes.
The weather bureau warned that scorched areas can be particularly prone to flooding, and that the burned debris and remnants from the fires can be carried in fast-moving waters.
Even with the deluge of rain there are still 31 fires burning in New South Wales, but none are considered an immediate threat.
The massive rainfall has also replenished water supplies in the region, which has been battling years of drought, with the Warragamba Dam, which supplies most of Sydney's water being replenished to 70 per cent. It was at only 42 per cent last week.
Tallowa Dam, Sydney's emergency water supply is up 100 per cent from last week's reading.
A severe weather warning is now in place for the entire coast of New South Wales, Australia's most populous state and where Sydney is located.
In the city alone, at least 200 people were rescued by emergency services over the weekend.
Reportedly, emergency services have dealt with thousands of calls for assistance from the public.
Several people have been injured, including four who were inside a car which was crushed by a falling tree in the city centre on Sunday afternoon.
Rail and ferry services in Sydney were also disrupted on Monday morning, with several platforms at one of Sydney's main stations, Central, left underwater.
Roads were flooded and access to train stations hampered.
Dangerous surf conditions are reported at places like Bronte Beach in Sydney with footage on Twitter showing strong waves and stormy conditions.
The state emergency minister David Elliott has urged Sydney residents to help rescue services by taking warnings seriously, staying away from flooding and keeping off the roads if possible.
Emergency services had advised people to stay home from work on Monday to avoid the disruption.
Thousands of people in low-lying areas of the city have been told to leave or get ready to leave their homes.
An area known as Collaroy in the Northern Beaches area has already seen significant damage from five metre high waves, with several metres of beach being washed away in places.
The full scale of the beach erosion was captured by drone footage.