The meteorological office has issued an El Niño alert and warns that a drought could strike later this year after years of heavy rains and flooding in the east of the country.
After two years of heavy rain and record flooding in the eastern states, La Niña is finally over, but officials warn more extreme weather in the form of drought could follow.
The Bureau of Meteorology issued an El Niño watch on Tuesday after long-range forecasts revealed a 50 percent chance of a pattern of warmer, drier weather this year.
More neutral weather is expected through the fall and winter, while warmer conditions could occur for the summer, said Andrew Watkins of the Bureau of Meteorology.
“Long-range forecasts show there is an increased chance of below-average rainfall for most of Australia during the autumn of 2023,” Dr Watkins said.
“But the northern rainy season, including the tropical cyclone season, for northern Australia continues through March and April, so there is potential for tropical weather systems to bring heavy rains to the north at times.”
Officials said the possibility of El Niño means an increased risk of wildfires.
There have been 27 El Niño events since 1900, and about 18 of them were affected by widespread winter and spring drought.
La Niña refers to the cold and often rainy phase of the ocean-atmosphere phenomenon that meteorologists call the El Niño-Southern Oscillation (ENSO), while El Niño is the warm, dry phase.
Scientists analyze year of weather disasters in Australia
Leading climate scientists have delved into some of the most extreme weather events Australians endured last year, and there was plenty to choose from.
Some of the country’s top scientific clients have deciphered the factors behind Australia’s disastrous and deadly year of extreme weather and weather.
Needless to say, devastating rain and flood events dwarfed all others in 2022 after La Niña broke rainfall records for the third time in a row across the country.
While the east coast was inundated with water, many other events were taking place, including extreme heat in the west and Antarctica, as well as wild winds and hailstorms.
Here’s a look at some of the events examined in the State of the Climate and Weather Extremes 2022 report.
The expert authors, from the Australian Research Council’s Center of Excellence for Climate Extremes, hope it will help governments and the public understand the complexity and nature of the climate extremes being witnessed.
Devastating floods in Qld and NSW:
The city of Lismore, in northern New South Wales, was the face of a devastating series of storms that inundated southeast Queensland and New South Wales in the first half of 2022.
Rainfall records were broken, with some regions experiencing more than five times what they would normally get in a month. It was the costliest flood in Australian history, with more than 20 lives lost.
In Lismore, flood waters rose two meters above the previous record, forcing families onto rooftops to survive.
Scientists say the flooding was the result of a combination of weather events.
First, the La Niña weather pattern meant that the basins were already soggy and primed for flooding.
Then, in late February, a wave from Rossby triggered the development of multiple rain-producing weather systems.
Rossby waves are building blocks of weather and are high-altitude, planetary-scale waves that greatly drive a variety of surface-level weather, according to the report.
They are disturbances in planetary waves, like the jet stream over Australia.
As the waves grow, they can break, just like on the beach.
A breaking wave event from Rossby, South Australia, was a major driver of the weather that inundated much of Queensland and New South Wales in February and March.
Sydney’s wettest year:
Just three weather events generated almost half of the staggering amount of rain Sydney received in 2022.
The city’s wettest year on record recorded a fall of 2,530 mm, more than double the average.
Atmospheric rivers, which work like conveyor belts and deliver relentless currents of moisture-laden air from the warm Coral Sea, and the shoals off the east coast were largely to blame.
Three events, in February/March, July and October, were responsible for 40 percent of the rainfall. The result was flash flooding in Sydney, significant flooding in the Hawkesbury-Nepean catchment, and forced the evacuation of 85,000 people.
A recent study from the ARC Center of Excellence suggests that the number of atmospheric rivers may increase by 80 percent by the end of the century under moderate and high emissions scenarios.
Heat record in WA:
A complicated combination of weather events saw Western Australia’s heat records fall in the summer of 2021-22.
In January, a strong high-pressure system over the Great Australian Bight brought hot, dry weather from the desert to Perth when a coastal trough blocked the sea breeze.
The result was six consecutive days above 40°C in Perth, the longest streak for any month in 123 years of observations.
The Pilbara region also endured a record heatwave, with the city of Onslow matching Australia’s hottest day on record when the mercury hit 50.7°C on January 13.
The previous month, suppressed tropical activity caused Marble Bar, also in the Pilbara, to briefly become the hottest place on the planet, reaching 46.2°C.
Heat waves are now one of the deadliest natural hazards in Australia and are expected to continue to worsen as the weather warms.
Antarctica feels the heat:
Last year was one of record sea ice loss and record heat in Antarctica.
In March, a heat wave hit, bringing temperatures more than 50C above average in some areas.
The same month also saw the collapse of part of the East Antarctic Ice Shelf the size of New York City, and the heat also caused the Conger Ice Shelf to collapse.
Antarctica also broke records for sea ice loss in 2022 and that has continued, with sea ice extent falling to a record low in 2023.
The minimum extent of Antarctic sea ice in 2023 was about 40% less than the average between 1981 and 2010.
That’s alarming because Antarctic sea ice reflects sunlight and influences air-sea interactions and ocean circulation, and is an important habitat for krill, which supports the Southern Ocean food web.
Sea ice also holds Antarctic ice shelves in place, which helps prevent sea level rise.
Wild winds on a double day of trouble
On the same day last November, severe thunderstorms ripped through parts of South Australia and the Northern Territory, leaving traces of damage.
The storms were part of a broad region of severe weather that spanned central Australia, and while both produced severe winds, they were very different.
Adelaide was hit by a line of storms that stretched for 140 km, producing gusts of over 100 km/h, causing transmission line failures and disconnecting the state from the national grid.
In Alice Springs, roofs were lost due to a single 10km-wide storm that produced a microgust, a strong wind event common in regions that have a deep layer of hot, dry air near the surface.
The scientists say more research is needed to determine how climate change will affect events like these in the future.
Hail hammers three states:
Destructive hailstorms hit Victoria, Queensland and NSW last year and farmers in particular were affected.
In the first weeks of 2022, large hail caused widespread damage to potato crops in Victoria and citrus and grape crops in New South Wales. Some grape growers lost half their crops.
Hail the size of cricket balls fell near Rockhampton in Queensland in October.
The following month, hailstorms swept through the Mallee region of Victoria, leaving millions of dollars in crop and property losses. Port Macquarie was also thrown causing extensive property damage.
Climate change affects the atmospheric properties associated with hail.
Experts believe that hailstorms may become less frequent but more severe as the weather warms, but also caution that the effect on hail remains highly uncertain.