Even Tasmania, which usually enjoys mild, temperate weather, endured its hottest day on record, as the temperature climbed to 107F (38C).  The heat was so oppressive that the massive increase in people using air conditioners caused a breakdown in Melbourne's electricity grid - leaving half a million homes without power.  The state's chamber of commerce estimated the economic cost of the weather at 100,000 Australian dollars.  On Friday night more than 200 people escaped the sweltering heat by attending a new cinema where an inflatable screen had been set up next to an outdoor swimming people - allowing viewers to cool off as they enjoyed the Will Smith film Hancock.  Some benevolent companies offered to let their employees leave early, but in a rare exhibition of presenteeism in January, workers decided to linger in their air-conditioned offices rather than take their chances on the baking streets below.  The soaring heat took its toll on the elderly and infirm, with police and ambulance crews in Adelaide, where temperatures hit 109F (43C), reporting a sharp rise in the number of sudden deaths, with at least 19 people in the city believed to have died as a direct result of the heatwave.  Most of those who died were aged at least 70 and at least 80 people were admitted to hospital with heat-related illnesses.  "Normally the ambulance service would have just a few [deaths] during a day, so this is a much higher number," said John Hill, South Australia's health minister.  "You've got to draw the conclusion that a lot of them have something related to the effects of heat."  Children were sent home from school and hotels reported a spike in bookings as hot home owners sought out fully-air-conditioned rooms.  But there is little respite in sight. Adelaide is preparing for its longest hot spell since 1908, with forecasters tipping temperatures above 107F (38C) for the next seven days.
The worst heatwave in more than 150 years has struck southern Australia, leading to at least 19 deaths and causing bushfires to rage across the parched outback.