Australia’s most devastating fires

Two of the most destructive bushfires in Australia occurred fairly recently. The Ash Wednesday bushfires of 16 February 1983 that swept through southern Victoria and South Australia were devastating. In all, 75 people lost their lives—47 in Victoria and 28 in South Australia. More than 300,000 hectares of land were burnt and 3,000 houses and other buildings were lost.

Ten months of dry weather and a hot summer produced a dry landscape, primed for fire. Temperatures (°C) were in the high 30s to mid-40s, the air was dry and there were gale-force winds.

There were already 104 fires burning that Wednesday, but by the afternoon several more were burning throughout southern Victoria. It’s not known exactly how all these fires started, but some were caused by powerlines clashing with each other and with trees. Some were deliberately lit.

Completely destroyed building after the 1983 Ash Wednesday bushfire — Aftermath of the 1983 Ash Wednesday bushfires. Seventy-five people died, 300,000 hectares of land were burnt and 3,000 buildings lost. Image adapted from: Sydney Oats; CC BY 2.0

The Ash Wednesday fires were the deadliest on record in Australia until the Black Saturday fires of February 2009.

Once again, there were hot, dry conditions, with extremely high temperatures and strong winds. On 7 February 2009, around 400 fires started in Victoria. Temperatures in the region reached the mid-40s. Around 12:30 pm, powerlines fell in Kilmore East, sparking a fire that went on to become a firestorm that devastated the communities of Kinglake, Strathewen and St Andrews.

Most fire activity occurred during the afternoon and early evening of Black Saturday. Although evening brought a cool change to the region, it was accompanied by strong turbulent winds. Burning a total area of around 445,000 hectares of land, the fires moved at an average speed of 12 km/h. One hundred and seventy three people were killed in the Black Saturday fires. More than 400 people were injured and 2,100 homes were lost.

The amount of energy released by the fires was estimated to be equivalent to around 1,500 Hiroshima atomic bombs.

A Royal Commission was established to examine the causes and consequences of the Black Saturday fires. Its final and interim reports are valuable sources of information on the impact of bushfires in Australia.