A rare weather event not seen for more than 20 years could lash parts of Australia with heavy rain for several months bringing more devastating flooding.
A ‘triple dip’ La Niña event looks likely to occur around spring, according to Weatherzone meteorologist Yoska Hernandez, despite the Bureau of Meteorology only announcing an end to the last La Niña cycle at the end of June.
“If La Niña events develop later this year, there’s a high chance precipitation will increase and be above average across eastern and northern Australia,” Ms Hernandez told Yahoo News Australia.
While it’s not yet known if the weather pattern will linger into 2023, it could drop the temperatures of Australia’s warmer months as we head into summer and result in fewer sunny days.
“When a La Niña event develops there is more cloud around, especially in eastern and northern Australia, so with more cloud around we would expect to see below average maximum temperatures.”
The phenomenon, which helped to drive heavy rainfall across Australia’s east coast over the past months, usually comes in pairs but occasionally will occur across three consecutive years.
The last time a “triple dip” La Niña occurred was more than two decades ago.
“In very rare situations La Niñas persist into a third year and it looks like this might be happening this year,” Dr Mike McPhaden previously told The Guardian.
“Triple dip La Niñas are rare. The last one was from 1998 until 2001 – so more than 20 years ago. This has the potential to be a triple dip La Niña that could go into early 2023.”
Flooding likely as second weather phenomenon strengthens
Even if a third La Niña event doesn’t eventuate, millions of Australians will still see above average rainfall over the coming months due to another weather phenomenon occurring in the Indian Ocean.
Similar to La Niña, a negative Indian Ocean Dipole [IOD] influences rainfall patterns but impacts areas around the Indian Ocean, including Australia.
The Indian Ocean Dipole (IOD) index just reached its lowest level in 6 years as a negative IOD pattern gains strength to the northwest of Australia. This increases the likelihood of above average rain in SE Australia over the coming months.
More details > https://t.co/ZrkHKCmTwz pic.twitter.com/SiQxiDrQAG
— Ben Domensino (@Ben_Domensino) July 11, 2022
Earlier this week, the IOD index reached its lowest level in six years, once again increasing the likelihood of above average rainfall for Australia’s southeast.
If both weather events were to occur at the same time, more rainfall would be likely and areas prone to flooding could be inundated yet again.
“With this phenomena developing, it has happened in the past where we have had remarkable flooding events,” Ms Hernandez said.
“So if those two come back later this year we will probably see flood events occurring again.”
Do you have a story tip? Email: firstname.lastname@example.org.