Wind, high temperatures and storms have hit Australia's eastern and central states, with firefighters on high alert and SES inundated with calls.
Fire danger, wind warning in NSW
Four children have been arrested, suspected of deliberately lighting a blaze at a scout camp at Lake Macquarie.
Sixty scouts have been evacuated and more than 10 homes are under threat across NSW as fires fanned by strong winds burn uncontrolled.
Properties are under threat at Shallow Bay in the Great Lakes, where an out-of-control fire has burned through more than two hectares of bush and grass.
Residents are being told to seek shelter and remain put because it is now too late to leave.
An emergency warning is also in place in Yarrowtich on the Northern Tablelands, where a bush and scrub fire is placing several properties at risk.
A blaze has also ripped through five hectares in Taree and jumped the Pacific Highway, closing all northbound lanes.
People in the area to the south of Old Bar Road are being urged to be wary of smoke and embers, with residents urged to leave now if the path is clear towards Old Bar.
RFS Deputy Commissioner Rob Rogers said there were concerns for properties there as well.
Other fires near Lake Macquarie have forced the evacuation of 60 Scouts at a Whitebridge camping area.
"They are all safe but there is multiple fires in the area in what would appear to be the work of an arsonist," Mr Rogers told Macquarie Radio.
Meanwhile, residents across New South Wales and the ACT are being told to prepare for wild damaging winds as a cold front moves across the region.
The SES on Thursday morning issued a warning for damaging winds averaging up to 80km/h and gusting to 120km/h in the Alpine peaks, with blizzard conditions expected in the Snowy Mountains above 1300 metres.
The SES is urging residents to tie down loose outdoor items and move vehicles inside and away from trees.
Storms blast Victoria with cold, wet weather
Stormy overnight weather and strong winds have triggered more than 100 calls for help across Melbourne, with trees uprooted, train stations flooded and power cut to homes in some suburbs.
The SES had received more than 800 calls for help by midday including more than 500 calls from metropolitan Melbourne.
About 2500 homes in Ballarat and Colac remained without power after 11,000 homes were hit by power outages across the state overnight.
A seven-year-old girl and a man in his forties were injured when a tree toppled over in high winds, crushing their car at Tarra-Bulga National Park in the state's east, shortly after 1pm.
Both were taken to La Trobe Regional Hospital in a stable condition, an Ambulance Victoria spokesman said.
A woman and two other children escaped unharmed.
Meanwhile, a Monbulk family had a lucky escape after a massive tree came crashing down on their home and car.
At Essendon, in Melbourne's north, a subway was flooded but cleared by about 7am (AEST) on Thursday while commuters faced big delays on some other rail lines.
A metal sheet blown off a building was found near the Sidney Myer Music Bowl.
Wild seas have also damaged Mount Martha's famous beach boxes.
An SES spokesman said the majority of callouts were for trees blown onto roads or building damage.
Bureau of Meteorology senior forecaster Gary Missen said wind gusts exceeded 100km/h in some parts of the city, reaching 102km/h at Avalon.
Essendon recorded speeds up to 92km/h.
Severe weather warnings remain in place for the state, however Mr Missen says he expects winds to die down on Thursday afternoon.
"We expect the wind to moderate in the next two to three hours and showers will start to ease off," Mr Missen said.
"There's only a couple more hours of it to go.
"By mid-afternoon tomorrow we expect most of the showers to have passed through and the atmosphere to dry out a little more."
There is little sign of relief from the record-breaking heatwave in outback Queensland.
Yesterday temperatures in a handful of towns reached unprecedented temperatures for the month of September.
Charleville, in the north of the state, reached 39 degrees - its hottest in 85 years.
Rick Threlfall from the Bureau of Meteorology told Fairfax today could see even more records tumble.
"More records could be broken today. We're expecting 40 degrees in Roma and 34 degrees in Toowoomba," he said.
"Fortunately, it will be a bit cooler in Charleville with a maximum of 38 degrees."
Brisbane, while not as hot as some other areas, is also not being spred from the heat, predicted to go well into the 30s by the afternoon.
Cleanup continues in SA
The cleanup is continuing across South Australia after strong winds whipped the state overnight.
Trees and powerlines were brought down right across the metropolitan area by gusts of up to 100kph, cutting power to around 8000 homes and businesses.
Electricity was even cut to the Channel 7 antenna at Mt Lofty, forcing a back-up generator to kick in to keep the station on air.
The falling trees caused havoc in many areas, including at on Waterfull Gully Rd in the eastern suburbs where wind brought down trees and a stobie pole, blocking the road.
A large limb from a gum tree fell onto a home on Taylors Ave at Morphett Vale, needing the State Emergency Service (SES) to come and remove it.