La Niña alert status raises flooding, cyclone risk
This status means the chance of a La Niña occurring this year has increased to 70 per cent, roughly three times the normal likelihood.
Bureau manager of climate operations Dr Andrew Watkins said La Niña typically resulted in above-average winter-spring rainfall for Australia, particularly across eastern, central and northern regions.
“It typically also brings cooler and cloudier days, more tropical cyclones, and an earlier onset of the first rains of the wet season across the north,” Dr Watkins said.
“The cooling of surface temperatures in the tropical Pacific Ocean and an increase in the strength of the Pacific Trade Winds indicates the chance of La Niña has risen. When these two changes occur at the same time, at this time of year, we see a greatly increased chance of a La Niña forming and persisting through spring.”
The last significant La Niña event was in 2010-11, which was Australia’s wettest two-year period on record – beating the previous record from the La Niña years of 1973-74.
Bureau data shows La Niña events typically see twice as many cyclones making landfall than during El Niño years on average.
The first cyclone to cross the Australian coast also tends to occur earlier in the season. The only years with multiple severe tropical cyclone landfalls in Queensland have been La Niña years.
This means an increased likelihood of major damage and flooding related to strong winds, high seas and heavy rains from tropical cyclones.
The Bureau said it would continue monitoring the situation closely.
For more information on La Niña and the impacts of past events, head to the Bureau’s ENSO Outlook page.