What flash droughts and a super El Nino will mean for your summer

Australian emergency services are bracing for a fire season supercharged not only by the intensifying “supersized” El Nino, but by the increasing threat of “flash droughts” which act “like hot air driers” blasting moisture out of soil and scrub faster the creeping droughts that have long been part of Australian life.

Where once relatively wet winters like the one just experienced across eastern Australia offered some protection through the fire season, increasing temperatures have made flash droughts more common, meaning relatively moist landscapes can suddenly become dry enough to feed fast and dangerous bushfires.

The recent series of heatwaves that rolled across Europe that contributed to a horror fire season resulting in the evacuations of more than 300,000 people is a perfect illustration of the phenomenon, says Greg Mullins, a former commissioner of Fire & Rescue NSW, and the founder of Emergency Leaders for Climate Action.

“Those heatwaves, over 35 degrees, very low humidity, and strong winds, they draw the moisture out of vegetation really quickly, so within a couple of weeks, you can be in a situation where it’s just like a drought that’s built up over a year or two years,” Mullins said.

“The hotter the atmosphere is, the more moisture it pulls out of vegetation.”

Flash droughts have only recently become a significant focus of study in Australia, but are known to be changing fire behaviour, says Dr Abhirup Dikshit, a specialist in the field with the University of New South Wales’ Climate Change Research Centre.

When they overlap with prolonged droughts, they create a “hyper-flammable” state which acts as an accelerant that can spread fires faster, see them last longer and grow larger than other wildfires, according to a paper co-authored by Dikshit published last month.

Scientists compared fires around the world between 2002 and 2021 and categorised them into four distinct groups: fires occurring under normal (no drought) conditions; fires occurring during flash droughts; fires occurring during isolated standard droughts; and fires occurring where the two drought types overlapped or followed one another.

Those that burnt during an overlap of drought and flash drought were 65 per cent larger than fires in normal conditions, and 21 per cent larger than those occurring during standard droughts alone. They spread 35 per cent faster and burned 19 per cent longer.

Writing about their findings, Dikshit and co-author Professor Jason Evans, also from the UNSW Climate Change Research Centre, described normal droughts to acting like an oven on the landscape, and compared flash droughts to a blast from a giant air dryer.

“When a standard drought turns into a flash drought, the effects don’t just add up; they multiply. Combined, they cause the fire danger to skyrocket, setting the perfect stage for fast-spreading and intense wildfires,” they wrote. “Short-lived weather anomalies such as flash droughts generate disproportionately severe and extreme fires.”

Dikshit’s research points to a sharp “turning point” in 2002–2003, after which flash droughts began accelerating and expanding.

Mullins said the growing body of scientific literature reflected his own experience fighting fires and studying fire behaviour.

“The ‘ah shit’ moment for me was the October fires we had in October 2013,” recalls Mullins.

At that point in the season, fires had never before caused major property damage, but after flash drought conditions struck, more than 200 homes were lost and an emergency declared. “I was commissioner at the time. We’ve never had major property losses in New South Wales before mid-November,” Mullins said.

NSW RFS fire behaviour analyst Laurence McCoy said that where fuels normally took four to six weeks of dry weather to “turn”, under flash drought conditions that could happen in a period of days. This change had not only had an impact on fire behaviour and risk, it could shrink the safe window in which hazard reduction burns could be conducted, he said.

He said that the increasing threat of flash droughts, combined with the intense El Nino that had developed, could make this summer particularly dangerous. “We know that each El Nino is different, and so we’re preparing for the worst, and hoping that perhaps the impact of this El Nino is obviously not as bad as it might be, but it is shaping up to be one of the strongest on record.”

‘We have never had ocean temperatures anything like it, and the implications are really, really scary.’Greg Mullins, former Fire and Rescue NSW commissioner

In Victoria, preparations have begun early for what authorities fear could be a “significant” fire season. “The CFA is aware of the potential for flash drought conditions and the impact rapid drying can have on vegetation and bushfire risk,” said the CFA’s Deputy Chief Officer Alen Slijepcevic. “These conditions have been factored into our planning for the coming fire season, with preparations commencing earlier than usual.”

Last week, the United Nations World Meteorological Organisation warned the El Nino that had formed was likely to be the strongest on record and extend into 2027.

A key indicator of the phenomenon, known as Nino3.4 index, measures sea surface temperature anomalies in central-eastern equatorial Pacific. It shows that temperature anomalies in the region have increased from an average 1.5 degrees above normal during May-July 2026 and 2 degrees above normal in July. Between late July and mid-August, they jumped again, ranging from approximately 2.2 degrees to 2.6 above average, indicating continued intensification.

Beneath the surface, ocean temperatures of 8 degrees above average were detected, showing there is enough heat in the system to sustain a prolonged El Nino.

The CSIRO notes there is not a linear correlation between the intensity of an El Nino and the impact on conditions in Australia, though the hotter and drier conditions associated with the phenomenon increase fire risk.

“El Nino is being supersized before our eyes,” said UN Secretary-General António Guterres when the measurements were reported. “The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up. Sea surface temperatures are rising, temperatures keep climbing, and the world is in the danger zone of extreme weather.”

The World Meteorological Organisation expects 2027 to be the hottest year on record, surpassing records set in 2024, 2023 and 2025.

Mullins said the situation scared him, noting that El Nino’s effects drove up average temperatures, which had already been forced up by about 1.5 degrees by climate change.

“It frightens me because I’ve watched this for many, many years. We have never had ocean temperatures anything like it, and it’s just the implications are really, really scary,” he said.

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Nick O’Malley is National Environment and Climate Editor for The Sydney Morning Herald and The Age. He is also a senior writer and a former US correspondent.Connect via email.Bianca Hall is The Age’s environment and climate reporter, and has worked in a range of roles including as a senior writer, city editor, and in the federal politics bureau in Canberra.Connect via X, Facebook or email.AdvertisementAdvertisement