Ash Wednesday fires
The Ash Wednesday fires were an Australian natural disaster which occurred in February 1983. The fires affected much of Victoria, including the Macedon and Dandenong Ranges, as well as the Otways in the sea. They also affected much of South Australia, mainly the Adelaide Hills. The Ash Wednesday fires were caused by the El Nino drought of 1982, where there was extremely low rainfall and high winds, mostly northerly. Another precipitating factor was a fire going on in eastern Victoria that went uncontrolled for almost a month. Many of the forests exploded with the wind conditions and lack of rain, creating many separate fires.
The human loss was 75 lives - 47 in Victoria and 28 in South Australia. In the Dandenong Ranges, 17 firefighters also lost their lives while they were fighting the fires. This was because of an abrupt change in direction. The Ash Wednesday fires were freaky in other ways too - a mattress was seen flying out of control in the Otways. 2,400 individuals and families also lost their homes.
The natural loss was over a 10,000 km² in Victoria and South Australia, including 5,200 km² which were destroyed in a few days of the fire.
http://sres.anu.edu.au/associated/fire/IUFRO/CONFLAG/ASHWED83/AWweath.HTM which is an inquiry about the specific fire weather event.