More than 300,000 homes in Victoria have been left without power after thunderstorms and wild winds lashed the state.
The Victoria State Emergency Service received more than 950 calls for help in the 24 hours to 7.30am on Friday, and the most affected areas include Ballarat, Bendigo and Melbourne's eastern suburbs.
There were 743 reports of trees down and 149 reports of building damage, and those numbers are expected to rise as Victorians report more damage.
More than 300,000 households are without power.
The Bureau of Meteorology has issued a severe weather warning for damaging winds across much of the state on Friday, with winds averaging 60 to 70 km/h and peak gusts of 100 km/h expected to develop along western and central Victorian coasts during the morning.
The winds will pass through Melbourne then extend to Gippsland in the middle of the day.
The highest wind gusts reported so far include 143 km/h at Mt William in the Grampians, 119 km/h at Melbourne Airport and 115 km/h at St Kilda.
Australia is on killer tornado alert as supercell thunderstorms sweep across the south-east of the country bringing floods, giant hail, dust storms and land gales. (Pictured, Thursday's devastating storm hits Adelaide)
More than 4000 lightning strikes were detected within a 400km radius of Maryborough, about 168 km northwest of Melbourne
The Department of Transport said speeds have been reduced to 40km/h across the West Gate Bridge due to the high winds, while buses are replacing trains on the Glen Waverley line between Darling to Glen Waverley due to a fallen tree.
Due to power outages, many sets of traffic lights are out, while there is the potential for fallen powerlines.
The department is urging Victorians to drive with care through all intersections and should they encounter fallen power lines stay clear to call triple zero.
'With high winds expected to continue this morning, drivers should be vigilant on the roads and ensure nothing distracts their focus from the road. Deferring your travel may be the best option,' it said.
The storm also caused widespread damage in South Australia, leaving more than 30,000 homes and businesses in Adelaide without power.
The state's emergency service is responding to 178 calls for help, mostly involving downed trees.
Australia is on killer tornado alert as supercell thunderstorms sweep across the country bringing floods, giant hail, dust storms, and high winds.
Urgent severe weather warnings were issued for South Australia, Victoria and parts of NSW as the dangerous storms grow overnight.
The Bureau of Meteorology warned the intense storms was a 'very dynamic situation'.
South Australia was battered by storms earlier on Thursday with golfball-sized hail smashing Adelaide before the weather system began to move east.
Ice and sleet ran like rivers through the streets of Adelaide in what locals called 'incredible, crazy weather'.
Up to 6,000 homes were without power, with Adelaide Hills among the areas worst hit and 2,500 families left in the dark by the devastating storm.
The storms are expected to reach their peak on Friday after building in strength through the night, with a severe fire danger warning for South Australia too.
The BoM warned of possible flooding in western and northern Victoria as well as possible dust storms, as high winds from the storm rips off dry topsoil.
'Nature is throwing a mixed bag at south-east Australia today and tomorrow with heavy rain, land gales, severe fire dangers and severe thunderstorms,' weatherman Jackson Browne said.
Urgent severe weather warnings have been sent out for South Australia, Victoria and parts of NSW as the danger storms develop and grow overnight.
The Australian Bureau of Meteorology warned the intense storms were a 'very dynamic situation.' (Pictured, the hail that smashed Adelaide on Thursday)
South Australia was battered by storms earlier on Thursday with golfball-sized hail (pictured) smashing Adelaide before the weather system began to move east
'Severe storms affected large parts of South Australia overnight and also Adelaide this morning with multiple reports of large to giant hail.
'With the system deepening rapidly today we're seeing a broad scale pick up in winds across the southeast with severe weather warnings for damaging wind.'
Throughout Friday, the storms will batter a wide section of NSW as temperatures soar up to 35C, stretching from Sydney all the way up to the Queensland border.
Elsewhere, a deep low pressure over Tasmania will bring heavy rain and floods to the south of NSW, Tasmania, and Victoria, and sea fog to the NSW south coast.
Ice and sleet ran like rivers through the streets of Adelaide (pictured) in what locals called 'incredible, crazy weather'
