Australia's south sizzled under near-record-breaking temperatures Thursday with Melbourne and Adelaide both recording 43 degrees and officials warning that heatwaves kill more people than any other natural phenomenon, dpa reported. Adelaide, briefly, was proclaimed the hottest city in the world by the Bureau of Meteorology as reports came in of birds falling out of the sky and a jump in hospital admissions. In Melbourne, in its longest run of 40-plus temperatures since 1908, over-stretched ambulance services are urging people to report only severe cases of heat exhaustion. Paramedics pointed to an eight-fold increase in calls so far this week. Lightning strikes have touched off thousands of forest fires, testing the mostly volunteer fire brigades.