Wild weather has battered Adelaide overnight, with strong winds, rain and a king tide sending water into homes and businesses.
The low pressure system is now tracking towards Victoria, with residents there warned to be on alert.
Heavy rain and winds of more than 100 km/h lashed parts of the state from Victor Harbour to the Yorke Peninsula.
Yesterday more than 30,000 residents lost power.
"There's mud everywhere, all of my mulch has gone for a swim downstream to my neighbours," a resident told 7News.
Drivers were stranded as water inundated cars, while thousands of residents spent the night without power.
Over 600 residents across the state called the SES for help with damage and flooding.
"We've had our 1 in 100-year flood I would imagine," another resident said.
Many residents were forced to evacuate their homes as winds fuelled a rare king tide that flooded low lying coastal areas.
"This is a significantly dangerous situation. We want people to stay away from the moving water and look after themselves," an SES spokeperson said.
In Melbourne, pedestrians ran for cover as heavy rain came down.
Conditions should ease later today in Adelaide but Victorians are being warned to be prepared for wind and rain, as the low moves east.
A severe weather warning for damaging winds has been issued across much of Victoria for Tuesday morning.
A flood watch message has been issued for northeastern Victoria, including the Upper Murray, Mitta Mitta, Kiewa, the Ovens and King catchments and Goulburn and Broken basins.
Damaging winds forecast in the northeast, west and south and east Gippsland districts during Monday evening - with gusts up to 120km/h forecast for alpine areas - are expected to continue in the early hours of Tuesday.
On Monday, homes were damaged by trees and flooding after a low-pressure trough from the southwest brought strong winds and heavy rain to metropolitan areas.
Ballarat and Mount William also experienced gusts of 82km/h, with winds of 113km/h recorded at Mt Hotham.