As much of the Australian continent endured intense heat yesterday, several small communities in Western Australia's Wheatbelt region were dealing with floodwaters.
On the east coast, several southern Queensland beaches on the Gold and Sunshine coasts were closed and swimmers plucked from rough surf as the incoming tide peaked.
Water conditions were being monitored hourly and more closures are on the cards today as the heatwave peaks.
There have already been several rescues in the rough conditions, including a young boy who suffered a suspected spinal injury in the surf at Burleigh.
A top of 39C is forecast in Brisbane today, with 36C expected on the Gold Coast and Sunshine Coast. Birdsville could set a new record for the state's hottest February temperature, with maximums of 46C and 47C tipped.
Paramedics have urged people to keep hydrated to avoid becoming ill as temperatures push more than 10C past the February average.
Relief from the heat isn't expected until Tuesday. In Sydney today temperatures will cool but parts of NSW are expected to face catastrophic fire danger.
The mercury was expected to surge past 40C in more than 50 of the state's citys and towns yesterday but Rural Fire Service Commissioner Shane Fitzsimmons said the real test lay ahead. Citing Australia's worst bushfire disaster, the Black Saturday blazes which claimed 173 lives in February 2009, Fitzsimmons said "the forecast indices are greater than those faced by Victoria at the time".
The monster hot air mass hovering over NSW had had "a baking effect" on vegetation, which meant extreme warnings would pose major risks.
The Bureau of Meteorology said very hot conditions associated with the mass of air and combined with fresh westerly winds over the southern half of the state meant severe fire danger for the Central and Southern ranges, Lower Central West and Hunter districts.
The mercury had nudged 44C in parts of Sydney's west by early afternoon yesterday and residents were bracing for an expected afternoon maximum of 48C. Strong wind warnings were also in place for Sydney, the Illawarra and far south coast at Eden.
NSW faced a possible lack of power supply yesterday and electricity use at Tomago Aluminium Smelter in Newcastle, which uses about 10 per cent of the state's power, was cut back.
In Western Australia water levels within the Avon River catchment are expected to rise over the weekend with up to 70mm of rain recorded in the 24 hours to Friday night, the Bureau of Meteorology said.
Flooding hit the community of Toodyay yesterday and moderate flooding was expected along the river in Beverley, with water under the town's bridge at 1.75m and rising.