· Australia among heatwave heavyweights

A cool change on Friday evening can’t come soon enough for residents in the south-east of the continent, with another day of scorching temperatures, bushfires and power outages.

In the southern capitals Melbourne reached 43.9 degrees on Thursday, while Adelaide got to 44.2 (slightly short of the predicted 46) and Canberra got to 40.1.

In Melbourne, a thunderstorm brought at least some cooler conditions to parts of the Victorian capital.

Striking pictures via @GettyImages: Australian Open 2014: Lightning Strikes In Melbourne http://t.co/RBkRrUA21M pic.twitter.com/pMVribnuSc

— HuffPostUK Pic Desk (@HuffPostUKPics) January 16, 2014

The temperature on Friday is tipped to reach 44 degrees in Melbourne, 42 in Adelaide, 41 in Canberra and 38 in Hobart, before the weather changes again on Friday evening.

Victoria

In Victoria, the heatwave affected Melbourne’s public transport system, with train delays affecting thousands of commuters.

Meanwhile, nearly 40 fires are burning out of control, with several warnings in effect in the Mallee and Grampians regions and residents in the worst-affected areas being advised to leave their homes.

A massive blaze burning in the Grampians, in the state’s northwest, is the biggest cause for concern as firefighters face some of the toughest bushfire conditions in the past five years.

Fire Services Commissioner said the change would cause very dangerous fire conditions.

“A gusty change sees fires potentially change in size and threaten different communities,” he said.

The 1500-hectare Grampians blaze is the result of two major fires that merged on Thursday after lightning strikes sparked a number of smaller flare-ups.

The Grampians National Park was closed and a number of surrounding towns faced an anxious night.

PIC This is the Grampians fire headed for Wartook and Laharum communities.@9newsmelb pic.twitter.com/yfkaQ5L0d0 — Alexis Daish (@LexiDaish) January 16, 2014

Residents in Steiglitz, near Geelong, are also being warned of a fast-moving fire.

The Victorian Premier Denis Napthine says forced power outages remain a possibility during the extreme heat.

The Energy Market Operator had warned it may have to force power outages, affecting up to 100,000 homes and business, due to near-record high electricity demand and constrained supply.

Dr Napthine says that scenario did not eventuate because Victoria did not hit peak energy demand.

But he told Fairfax Radio people should still avoid non-essential electricity use today and tomorrow.

Victorian fire authorities have issued warnings over two out-of-control bushfires burning near the Grampians National Park and one in the Big Desert National Park near Telopea Downs.

Melbourne is facing its longest run of 40 degrees days since 1908, when there were five straight.

The temperature did not drop below 27.2 degrees in the Victorian capital on Wednesday night and the mercury was sitting at 42.4 at 3:20pm (AEDT).

Hundreds of firefighters have been deployed along with eight water-bombing planes to the Grampians fires, while residents have been advised to leave their homes immediately

Victoria’s ambulance service is also recording a spike in heat-related cases with paramedics treating 243 people between Monday and midday Thursday, an eight-fold increase.

Ambulance Victoria operations manager Paul Holman said Victorians need to think about their situation before calling an ambulance, with paramedics receiving one phone call about a sore throat.

“If you are suffering chest pain or any other serious medical condition, then certainly call triple-zero. “However if it is something less urgent then just think about whether a doctor, Nurse On Call, a relative or some other service is more appropriate.”

The state has also had a jump in cardiac arrests, with 26 cases on Wednesday and another 16 before midday on Thursday, double the average.

Sudden windshift 4 hours ago, North-West of Moe, Victoria, Australia #bushfires #nothelping pic.twitter.com/KAtOLNpGJI — Greg Faull (@greg_faull) January 16, 2014

The heat took a heavy toll on spectators at the Australian Open.

WAAP Emergency Services Minister Kim Wells said St John’s Ambulance staff have treated 970 tennis fans for heat exhaustion during the tournament.

Australian Open organisers invoked the extreme-heat policy for the first time on Thursday afternoon as temperatures topped 43 degrees.

South Australia – Adelaide is Earth’s hottest city

Adelaide was confirmed as the hottest city in the world by the Bureau of Meteorology soon after midday and the mercury sat at 43.5 degrees Celsius at one point this afternoon.

Local firefighters say Friday will be the worst fire danger day of the heatwave, with the triple threat of extremely high temperatures, rising winds and thunderstorms.

Chief officer Greg Nettleton says crews are bracing for changing conditions as a wind shift and eventually a cooler change sweeps across the state later on Friday.

The Country Fire Service is battling a string of fires on the west coast, Eyre Peninsula, in the mid-north, the southeast and the Riverland.

An emergency warning has also been issued for an out-of-control fire burning in Bangor in SA’s Southern Flinders Ranges near Port Germein Gorge, while a fire at Kiama has broken containment lines and is threatening a house.

Ben from #ChristiesBeach patrols helping a koala beat the #heatwave today in #Adelaide #police #KOALAtypicture pic.twitter.com/srA4fplJMR

— SA Police News (@SAPoliceNews) January 16, 2014

As the mercury passed 43.7 degrees, the weather bureau’s John Nairne said Adelaide had indeed earned the dubious title of hottest city on Earth, albeit temporarily.

The day’s heat followed very hot conditions overnight, when the temperature only dropped to 29.9 just before 6:30am and remained above 35 degrees at 2am.

The Adelaide record high of 46.1 degrees, which remains unbroken, was recorded during the January 1939 heatwave.

Senior climatologist Darren Ray agrees a cool change expected on Friday might come later than originally forecast.

“There’s actually some indications now that the change might be a little bit slower than we anticipated a day or two ago,” he said.

“It’ll be a hot day to start with on Friday and what the temperature reaches on Friday will depend highly on how quickly that change pushes through.”

South Australians have been warned to prepare for rolling blackouts as authorities try to reduce the pressure on electricity grids.

The SA Government has confirmed power could be switched off to suburbs to prevent a system meltdown as air-conditioners kick into overdrive.

The heatwave is taking its toll on a colony of flying foxes, with about 90 found dead on the ground in Adelaide’s Botanic Park.

Many of the creatures, which have travelled from the eastern states, have dropped from the trees either dead or dehydrated.

Canberra/ACT

Canberra was experiencing another hot day after Wednesday’s maximum of 40.2C nudged the January record set in 1968, falling shy by just 1.2 degrees.

The temperature gauge was sitting at 39.6C at 4:30pm Thursday, with 41C forecast for Friday.

Tasmania

Fire crews across Tasmania are on high alert today as the state braces for extreme temperatures.

The weather bureau expect parts of the south-east will hit 40 degrees and temperatures in Strahan, Swansea and Launceston to hover around the mid 30s.

A total fire ban is being enforced.

Chief Fire Officer Mike Brown says extra crews in regional areas will be ready to respond to the conditions.

“We’re also expecting wind speeds to be slightly stronger and there’s likely to be a fair bit of atmospheric mixing too,” Mr Brown said.

“So there’s some fairly confused weather patterns, particularly around the centre of the state.”