We know heatwaves and drought can turn bushfires into infernos, but the reasons why were poorly understood in science.
Long heatwaves during entrenched drought often trigger fears of bushfire. It’s easy to imagine rolling days of hot, dry weather desiccating leaves, bark and twigs, transforming them into a potent fuel.
Victoria’s heatwave in 2009, which reached a record temperature of 46.4℃, came during severe, enduring drought and culminated in the Black Saturday bushfire tragedy. Likewise, the unprecedented Black Summer bushfires marked the end of 2019, Australia’s warmest and driest year on record. It unfolded in episodes of extreme heat combined with dry, windy conditions.
While we know heatwaves and drought make fires worse, the details are poorly understood. This is what our new research investigated. We found drought and heatwaves intensify the drying of dead bushfire fuel, and can lead to “megafires” like those we saw last summer. However, we were surprised to find the effect varies in nature over different regions.
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Image via University of New South Wales Sydney
