With more than a hundred bushfires burning, record breaking temperatures, and extreme winds, New South Wales, australias most heavily populated state, has declared a 7 day state of emergency. Two volunteer firefighters have been killed in a road crash near sydney. Temperatures as high as 47 celsius are expected at the weekend. And Prime Minister Scott Morrison is taking some criticism for being on holiday as the crisis unfolds. Hes now released a statement saying, i express my sincere condolences and sympathies to the families of the firefighters who have so tragically been killed overnight, and adds that he will be returning to sydney from leave as soon as can be arranged. With more on the bushfire emergency, our science editor, david shukman. A roar like a jet engine as the flames advance. A line of trees is suddenly ablaze. In record heat and parched conditions, at least 50 of the fires are out of control. Lets get out of here, bro. This is an emergency on dozens of fronts. House by