Fire-generated thunderstorms in Australia and last month’s deadly US tornadoes have highlighted rising risks from convective storms, the New York-based Insurance Information Institute says.

Population growth and economic development are contributing to increasing losses from convective storms, a paper from the industry-owned institute says. At the same time, research suggests the geography, frequency and intensity of storms may be changing.

“2019 was the fourth straight year in which convective storm-caused insurance payouts topped $US20 billion ($31 billion) globally, with most of them driven by US hail and wind outbreaks,” Senior Research Analyst Jeff Dunsavage said.

The report warns that thunderstorms generated by pyro-cumulonimbus clouds during bushfires could also become more frequent, potentially worsening impacts from the events.

“When fires get big enough they can create their own weather systems,” the report says. "The fire-breathing dragon of clouds generated by the recent fires in Australia is just one example of how weather events can spawn intense fires.”

The white paper notes that Australia’s fires were barely extinguished before parts of the country were hit by thunderstorms and golf-ball sized hail.

In the US, hailstorms in the US seem to be generating larger stones capable of inflicting greater damage, and storms are no longer just in areas traditionally prone to the events.

Tornadoes killed 40 people in the US last month, the highest monthly death toll from the events since 2013, but the institute says it is difficult to tell if their frequency is increasing given radar advances and the “growing ‘hobby’ of tornado chasing”.

Actions to address convective storm risks could involve improved forecasting, better building standards, early damage detection and remediation, and increased risk-sharing with customers through deductibles and parametric offerings.

Click here to read the report.