With the heat wave in central and southern Australia stretching into its second week, meteorologists with the Australian Bureau of Meteorology have added two new colours to their temperature maps to better represent the extreme heat.

Previous forecast maps capped the temperature-colour scale at 50 degrees Celsius, which was shown as black. Tuesday's forecast was predicting temperatures of between 52 and 54 degrees C this week, though, so in order to keep the public properly informed of the risks, forecasters added the colours purple (51-52 degrees) and magenta (53-54 degrees) to represent these extremes.

According to the bureau, the highest temperature recorded so far in the heat wave was on Monday, in the town of Leonora, Western Australia, where the mercury rose to 48.3 degrees Celsius, and the average temperature for all of Australia on that day set a new record at 40.33 degrees, beating the 1972 record of 40.17 degrees C.

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"What makes this event quite exceptional is how widespread and intense it's been," said Aaron Coutts-Smith, the bureau's New South Wales manager for climate services, according to The Australian. "We have been breaking records across all states and territories in Australia over the course of the event so far."

The persistent heat wave is being caused by high pressure cells (hot, dry weather patterns) passing over the continent, however they are being blamed, ultimately, on climate change.

"In recent studies we have analysed how extreme temperatures have changed globally," said Dr. Markus Donat, a postdoc researcher at the Climate Change Research Centre at the University of New South Wales, according to The Australian. "For most regions, including Australia, we found that extremely high temperatures have become more frequent and more intense."

"Counting the number of very warm days (defined as the warmest five per cent between 1951 and 1980) we found that during the most recent three decades... the frequency of days in this warmest category has increased by 40 per cent globally," he added.

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The blistering, tar-melting heat, which has already sparked numerous wildfires, is expected to last at least the rest of this week.