Projected changes in hail damage potential in Australian cities under climate change

Hailstorms are a leading contributor to insured losses in cities in Australia and are expected to be affected by climate change, yet changes to hailstorm damage potential under climate change are not well quantified. Hail damage grows with the size of the hailstones produced by a storm, and is exacerbated by the co-occurrence of strong winds. Here, we show the first projections for hail size and co-occurring wind strength for Australian cities under a climate change scenario. Convection-permitting downscaled simulations were run for major cities and a remote region, in total covering 65% of Australia's population, for a historical period and a scenario with ~2.8 degrees Celsius of global warming over pre-industrial temperatures. Using extreme value analysis, we show that in the future scenario hail damage potential increased in some regions. In particular, overall hail frequency was projected to increase around Sydney/Canberra and Brisbane, while there were projected increases in maximum hail size for domains covering Melbourne, Sydney/Canberra, a remote region in Western Australia, and Perth. Strong winds coincident with hail were projected to decrease around Melbourne, Sydney/Canberra, and Perth. These results are important for urban design and city planning in a changing climate and can inform future climate risk planning in Australian cities.