The Sydney region is at increasing risk of damage from flash flooding as a result of increasingly intense short rainfall bursts, climate researchers have warned.

Research using Bureau of Meteorology radar data from overlapping stations at Newcastle, Terrey Hills and Wollongong has found a 20% per decade increase in the intensity of rapid bursts.

“An intensification of 40% in only two decades means we must re-evaluate existing flood control systems and standards,” the scientists say in an article published on The Conversation website. “We also need to explore whether it is happening elsewhere or unique to Sydney.”

The article, by University of Melbourne Research Fellow Hooman Ayat and UNSW Climate Change Research Centre professors Jason Evans and Steven Sherwood, outlines findings they have published in the latest issue of the journal Science.

The findings are consistent with expectations from a warming climate but further study is needed into drivers of the change, the researchers say.

“We looked at things like El Nino and other modes of variability in the climate system and it’s not related to those so it leaves climate change as one possibility,” Professor Sherwood said.

“We do think that in a warmer climate the atmosphere is becoming more unstable and that means that you do expect bigger bursts of rain in a really short timescale.”

The rapid rainfall burst events, which are typically highly localised and can be part of a larger storm or form independently, have been difficult to study in the past.

The main barrier has been the small-scale nature of the events, which are hard for typical observational instruments such as rain gauges and satellites to capture, while climate models also can’t directly simulate rapid rain bursts, the article says.

The article is available here.