By Chris Clarke
Queensland could expect a much-increased risk of heavy rainfalls and flash flooding later this year as the possibility of a 4th La 狈颈帽补 in 5 years looms.
Conditions are only just now returning to 鈥渘ormal鈥� following a summer of El Ni帽o, which saw cyclones and destructive thunderstorms storms plague the State following a dry spring with bushfires.
But already climatologists are preparing for the possibility of another swing towards the opposite end of the scale.
Australia experienced 3 straight La 狈颈帽补 summers between 2020 and 2022 before El Ni帽o last summer.
As a result, vegetation and rivers are still waterlogged.
believes the potential for an increase in flash flooding is high if the current early prediction of another La 狈颈帽补 proves correct.
鈥淭o go from 3 consecutive La 狈颈帽补 summers to a strong El Ni帽o this past summer, and then a rapid swing back to La 狈颈帽补 is very unusual,鈥� he told Research News.
鈥淟补 狈颈帽补 events historically have occurred every 3 to 5 years.
鈥淲ith it, there is an increased risk of flooding, particularly flash flooding if catchments remain near saturated.鈥�
La 狈颈帽补 is a cooling of equatorial ocean temperatures in the central and eastern Pacific Ocean.
International climate models indicate Australia would experience a mild winter with temperatures above average and rainfall near average.
Above average rainfall would very likely then occur in the summer.
In its latest climate update, the Bureau of Meteorology said 3 of its 7 international models pointed to
鈥淭he oceans have been the warmest on record globally since April 2023,鈥� the statement read.
鈥淪ea surface temperatures continue to increase with temperatures in February 2024 setting a record for that month, and March 2024 on track to be the warmest March on record.鈥�
Meanwhile, the National Oceanic and Atmospheric Administration (NOAA) has estimated that the probability of La 狈颈帽补 returning exceeds 80 per cent by spring.
La 狈颈帽补's average occurrence is once every 4 years, and an occurrence of 4 in 5 years has only occurred twice since 1900.
Professor McGowan said he was concerned weather will become more extreme in coming years due to 鈥渢he Earth system being out of energy balance due to anthropogenic global warming鈥�.
鈥淭he big unknown is how ocean temperatures will change from their exceptionally warm state at present,鈥� he said.
鈥淟补 狈颈帽补 should see above average ocean temperatures persisting in the western Pacific and around east and northern Australia in the 2024/25 summer.
鈥淚f this occurs then the 2024/25 monsoon is likely to be more active with an increased risk of tropical cyclones including along the Queensland coast.鈥�
What La 狈颈帽补 means for Queensland鈥檚 infamous summer thunderstorm season though is still uncertain.
鈥�Published research shows little influence of large-scale climate drivers such as ENSO on thunderstorms,鈥� Professor McGowan said.
鈥淓vidence is emerging however of increased thunderstorm rainfall and rainfall intensity which increase the risk of flash flooding. The is linked to the observed increase in global warming and the ability of a warmer atmosphere to hold more moisture.鈥�
