17 Dec 2015, 9:22 AM UTC
Extreme heat sends SA temperatures above 40 degrees Celsius
There has been another day of extreme heat across much of South Australia, with Adelaide's maximum temperature hitting 42.9 degrees Celsius in the middle of the afternoon. Temperatures were in the 40s across many parts of the state and nudged the mid-40s in places including Port Augusta. There was some relief from the heat for anyone prepared to head far enough west, as it was a pleasant 25C at Ceduna in the early afternoon. The hot spell in Adelaide is tipped to officially become a heatwave on Friday if the city reaches more than 40C. The weather bureau is tipping a top of 42C. Its definition of a heatwave for Adelaide is five consecutive days with maximum temperature at or above 35C or three consecutive days at or above 40C. John Nairn from the Bureau of Meteorology said , this burst would be the most severe December heatwave on record. "That is a record and it is a very severe, significant heatwave," he said. "It is an unusual event. "These are the sorts of signals you will see with climate change where we see the very high temperatures spread out from where they normally used to be." Adelaide Metro warned commuters some trains were travelling at reduced speeds because of the risk that prolonged heat had affected sections of track. The State Emergency Service said people needed to be aware branches could fall without warning from trees which were stressed by the extreme weather. Its personnel dealt with a number of callouts, including at Tea Tree Gully in the north-east suburbs. Five districts will have total fire bans on Friday with severe danger ratings â€” the Mount Lofty Ranges, Murraylands, Riverland, Mid North and Flinders. A mild change is expected to reach western parts of SA on Saturday and areas further east on Sunday. But the heat is expected to return with the weather bureau forecasting a top of 39 degrees for Christmas Eve in Adelaide.