Projected changes in hail damage potential and swath properties over Australian cities under global warming

Hail is a leading cause of property and crop damage in Australia, with individual events capable of inflicting over $1b worth of insured losses. Hail damage is increased if hailstones are larger, if there are coincident strong winds, and if hail swaths cover larger areas. Australia’s most populated region is also its most hail prone, meaning the country has high exposure to hail hazard. While hailstorms are expected to be affected by climate change, the details of changes are non-stationary and subject to high uncertainty. Here, we use downscaled simulations over major Australian cities to examine projected changes in hail frequency, damage potential, and swath properties under a climate change scenario with ~2.4 degrees C warming. The areas we consider cover more than 65% of Australia’s population. We used extreme value analysis to analyse changes in maximum hailstone size and hail-proximal wind speeds. We used object-based analysis to summarise swath properties and compare them between epochs. The simulations project increases in hail frequency in Sydney/Canberra and Brisbane regions, increases in maximum hail size around Melbourne, Sydney/Canberra, Kalgoorlie, and Perth, and decreases in hail-proximal wind speeds around Perth, Melbourne, Sydney/Canberra. This study provides the most comprehensive projections for changes in hail damage potential under climate change in Australia to date.