New research from the University of NSW has revealed that the number of “hail-prone” days for heavily populated areas in NSW and WA has increased by as much as 40%.  

Leading atmospheric researcher at the UNSW’s Climate Change Research Centre Tim Raupach says eastern NSW cities such as Sydney, Newcastle and Canberra, as well as Perth, face an increased likelihood of hailstorm events, although risk has decreased across most other parts of the country.

The researcher defines “hail-prone” days as any day when an unstable atmosphere has all the required “ingredients”, such as moisture and changing wind shears, to cause hail. He notes that hailstorms are “hard to measure” and create obstacles in outlining changing patterns.   

“Because of this, we don’t really have a good idea of how they have changed over time, or how they are projected to change into the future,” Dr Raupach said.

“We wanted to produce a continental map of how hail hazard frequency has changed across Australia, and to be able to look into what atmospheric changes are driving these patterns.”

Dr Raupach says, typically, it would be understood that the effects of climate change would decrease the possibility of hail, given the warming temperatures, but he highlights that greater volatility in weather can also have an impact.

“Where you have increased instability, then you might get more generation of hail and larger hailstones being generated in those regions that might survive more melting,” Dr Raupach said.  

“But where you have decreases in instability, then you have kind of a dampening effect.”  

Hail damage accounts for one of the most significant causes of insured losses annually, with the 1999 Sydney hailstorm on record as the country’s second costliest natural disaster, only behind last year’s February and March floods in Queensland and NSW.  

“This is essential information for the agricultural industry, because hailstorms can raze crops, the insurance industry, because of the damage hail can cause, and for city planning,” Dr Raupach said.  

“Hail is really one of the driving factors in the year-to-year costs for the insurance industry. The industry is interested in understanding how this hazard might change in the future.”  

He says he is hopeful the research can be utilised in future planning of resilient infrastructure for cities and farmland.  

“We need to think about resilient agriculture that can deal with potential increases in the hail hazards, if they were to continue into the future, and likewise, how we can protect our densely populated areas from damage due to hailstorms,” Dr Raupach said. 

Click here for the research.