Melbourne cooling after hottest night in 100 years

Effects of a bush fire in Kinglake, Victoria in June 2009. File photo / Supplied

CANBERRA - Australia endured another day of deadly heat yesterday as temperatures in three states soared well into the 40s and people fled towns and parks as fire danger climbed to the code red alert of catastrophic danger.

Adelaide, in South Australia, sweltered through its fourth successive day above 40C, surrounded by a tinder-dry state which declared total fire bans in 10 of its 15 fire districts.

3.4mm of rainfall eased Tuesday's temperature in Adelaide down to 18.4 degrees early this afternoon.

Melbourne endured its hottest night in over 100 years. The temperature dipped to a minimum of 31.3 degrees Celsius just before 1pm (AEDT) on Tuesday after a sweltering maximum of 43.6 degrees.

The record to beat was set 108 years ago, on February 1, 1902, when the temperature in the city fell to just 30.6 degrees.

Meanwhile, more than 30,000 customers have suffered power cuts after the extreme weather caused distribution transformers to overheat.

Jemena and United Energy customers in the south-eastern suburbs and the Mornington Peninsula endured rolling outages from late afternoon on Monday.

At 7am on Tuesday power had been restored to more than 25,000 customers and about 2,200 were waiting to be reconnected.

A spokesman for the two power companies said the problem worsened overnight but only about 200 customers were affected at a time.

With Melbourne's temperature reaching up to 43C, Victorian officials were warning people to get out of the Wimmera region as the fire threat reached a pitch similar to last year's disastrous Black Friday conditions.

A total fire ban was imposed across the entire state.

Large areas of New South Wales and Western Australia were also in severe or extreme danger, and a total fire ban was imposed in all areas of Tasmania.

As these states fried, the Bureau of Meteorology issued flood warnings for parts of the Northern Territory - following a deluge in Alice Springs that swept two children away on Sunday - and several rivers in Queensland.

Although a cool change is expected to bring relief to many areas in the next few days, the latest heat wave has confirmed warnings that this will be one of the most dangerous summers in modern history.

In Adelaide the State Emergency Service issued an extreme heat warning, urging people to take precautions to avoid a repeat of the tragedy of last summer's nine-day heat wave, which killed 58 people.

So far only a small number of people have been admitted to hospitals with heat-related problems, but the SES warned residents to drink plenty of fluids, wear loose clothing with broad-brimmed hats, avoid outdoor activities and check regularly on elderly relatives, friends and neighbours.

They also warned of other potential dangers: sudden phone and power failures, extreme heat in parked cars, and large, heat-stressed trees dropping branches without warning.

Similar concerns were echoed in Melbourne, where power demand soared as the mercury rose, and commuters were urged to take water with them.

Police are also warning people to watch for arsonists, who have already been responsible for major fires in several states this summer.

In Adelaide fire-fighters defeated a number of deliberately set outbreaks on the city's fringes, and in Victoria Police Chief Commissioner Simon Overland said police were watching for firebugs.

Two alleged arsonists were arrested in Victoria last week.

Fears increased yesterday afternoon when smoke was reported in the St Arnaud Range National Park in the Wimmera region, where the code red alert prompted warnings to leave parks, holiday camps and their homes.

The report was a false alarm, but the danger remained.

"If people haven't left their homes they should really leave early and move to a safer place, whether that be a town or open area or - if they can - drive all the way down to the beach," Sustainability and Environment Department spokesman Dennis Ward said yesterday morning.

ABC radio later reported that the warning was being heeded, with people leaving the town of Hall's Gap and holiday sites emptying.

Firemen fought a number of grass and scrub fires in South Australia yesterday, but by late afternoon they were no longer a danger, despite the conditions.

But in the west of the state a new threat was developing as a storm front threatened to lash parts of the coast and inland pastoral areas with thunderstorms, winds gusting to 90km/h, and flash flooding.

And in Tasmania, where Hobart sweltered in 36C and a total fire ban was declared across the state, fire-fighters battled about 20 grass and scrub fires.

They also finally contained a week-long, 3000ha fire that at one stage threatened York Town and Beaconsfield in the state's north.

- NZ HERALD STAFF, AAP