Purple alert! Australian heatwave forces climate experts to use new colour to represent extreme temperatures

Australian Bureau of Meteorology adds two entirely new colours – deep purple and pink – to show the new extreme range on its interactive weather maps

Australia’s giant and record heatwave, which is sparking hundreds of bush fires across the land, has forced the country’s meteorologists to redraw their national temperature scales – upwards.

In an unprecedented move, the Australian Bureau of Meteorology has extended the temperature range on its charts from the previous cap of 50 degrees Centigrade – 122 degrees Fahrenheit – to 54 degrees C, which is more than 129 degrees in Fahrenheit terms.

At the same time, it has added two entirely new colours – deep purple and pink – to show the new extreme range on its interactive weather maps. A patch of purple, indicating 50+, is now visible on one of the temperature charts for next week.

This is thought to be the first time that any country in the world has actually redrawn its charts to take account of temperatures which are thought likely to go off the scale which had been previously applied, and climate scientists indicated it was a warning for the future.

'”The current heatwave - in terms of its duration, its intensity and its extent - is unprecedented in our records,” said the Bureau of Meteorology's manager of climate monitoring and prediction, David Jones.

''Clearly, the climate system is responding to the background warming trend. Everything that happens in the climate system now is taking place on a planet which is a degree hotter than it used to be.''

The scorching temperatures could last into the weekend and beyond, Dr Jones said, potentially breaking the country's all-time high of 50.7 degrees C – 123.6 degrees F – set on January 2, 1960 at Oodnadatta Airport in South Australia.

Bob Ward, spokesman for the Grantham Institute for Climate Change in London, said tonight: “It is a measure of just how extreme this heatwave is that a national meteorological organisation is struggling to re-calibrate its monitoring methods by adding an extra four degrees to its scale. It is a sign of things to come.”

Hundreds of bushfires raged across southern Australia today as the country sweltered in what was almost certainly its hottest day on record, although, in what one politician called “a remarkable escape”, no lives were lost, and relatively few properties destroyed.

Worst affected were New South Wales, where more than 130 fires were still burning tonight, 30 of them out of control, and Tasmania, where fires flared up again, threatening a clutch of seaside towns on the already hard-hit Tasman Peninsula.

Records are tumbling daily as Australia endures the same “catastrophic” fire conditions which prevailed in rural Victoria during the 2009 infernos in which 173 people died. Yesterday was the hottest day nationally since records began, with an average maximum of 40.33C – 104.6F – and today looked set to overtake it once calculations were completed.

The heat was so extreme that Outback roads melted. "It’s like someone put the hairdryer on your face,” said Eva Toth, a motel owner in Tarcutta, one of several NSW towns under threat, as she packed up a few belongings and prepared to flee.

Searing heat, strong winds and low humidity have combined to create lethal fire conditions across southeastern and central Australia, exacerbated by an abundance of fuel. “You don’t get conditions worse than this,” said Shane Fitzsimmons, head of the NSW Rural Fire Service.

In the southern NSW town of Bega, it was already 37.8C (100 degrees F) at 9am today, the mercury having risen nearly15 degrees in an hour. In Sydney, where thousands of homes suffered power cuts thanks to soaring demand for air-conditioning, it was still 34C- 93F - at midnight last night.

The hottest place in Australia was Warburton, in the Northern Territory, which recorded 47.2 degrees, or 117 Fhareinheit. “The bitumen road’s melting, but you don’t really blame it,” said one local, Lynnie Plate.

In the cities, people sought refuge yesterday in air-conditioned libraries and cinemas. Extra surf lifesavers were on duty at beaches. At Sydney’s busy railway stations, staff handed out bottled water. At the city’s Taronga Zoo, keepers hosed down the animals and fed them on frozen carrots and meat ice block.