While many different climate drivers can influence Australia’s weather, it’s important to know what natural cycles and patterns increase the chance of storm or flood.
Take, for example, El Niño and La Niña. These are complex weather patterns, or phases, that have the strongest influence on our country’s year-to-year climate variability. They form part of a naturally occurring climate cycle called El Niño-Southern Oscillation (or ENSO). This cycle occurs roughly every 1 to 8 years, lasting between 6 to 8 months at a time.
For us, El Niño typically leads to warmer, drier conditions over eastern Australia, while La Niña usually leads to cooler conditions – with increased rainfall across much of the country.
As the Bureau of Meteorology recently declared, La Niña is now underway. Meaning we can expect a much wetter summer – particularly people residing in north and east Australia. The last time we experienced a “strong” La Niña period was between 2010 - 2012, when parts of Queensland and New South Wales saw record rain and flooding.
What La Niña means for us
While every La Niña is different, there are certain signs to take note of.
● Increased rainfall across much of Australia
● An increased chance of widespread flooding (as seen in 2010 - 12)
● Greater tropical cyclone numbers
● Cooler daytime temperatures (for those south of the tropics)
● Warmer overnight temperatures (for those in the north)
● A shift in temperature extremes
● Decreased frost risk
● Earlier monsoon onset
How will La Niña impact storm season?
We’re likely to see above-average cloudiness and rainfall during winter and spring, particularly across the east and north of Australia. Naturally, this boosts the chance of widespread flooding. The last 12 out of 18 La Niña events have resulted in floods across Australia – with the east coast experiencing twice as many severe floods during La Niña years than El Niño years.
We’re also likely to see more tropical cyclones – with the first likely to occur earlier in the season – plus an increased chance of landfall. This means Queensland residents, in particular, need to be more alert around major building and/or street damage caused by strong winds, high seas and heavy rains.
Learn where Australia’s high-risk flood areas are and/or how to develop an emergency flood plan here.
This article above contains information from The Bureau of Meteorology. Articles referenced: Bureau of Meteorology raises La Nina status to active (2020) (verified 27/01/2021) and What is La Niña and how does it impact Australia? (2016) (verified 27/01/2021).
This page provides general advice only. For up-to-date and specific advice relating to the risks in your area please speak to your local council or emergency services.