During La Niña events, rainfall typically becomes focused in the western tropical Pacific, leading to a wetter than normal period for eastern, northern and central parts of Australia, according to BOM’s head of operational climate services, Dr Andrew Watkins.
“La Niña also increases the chance of cooler than average daytime temperatures for large parts of Australia and can increase the number of tropical cyclones that form,” Dr Watkins said.
“La Niña is also associated with earlier first rains of the northern wet season, as we’ve observed across much of tropical Australia this year.”
La Niña is likely to persist until at least the end of January 2022.
Dr Watkins added that the last significant La Niña was 2010–12. This strong event saw large impacts across Australia, including Australia’s wettest two-year period on record, and widespread flooding. However, he said that this year was not expected to be as strong as 2010-12 and might even be weaker than the La Niña that also occurred during spring and summer of 2020-21.
“Every La Niña has different impacts, as it is not the only climate driver to affect Australia at any one time. That's why it is important not to look at it in isolation and use the Bureau’s climate outlooks tools online to get a sense about likely conditions for the months ahead,” Dr Watkins said.
Catalyst for more all-weather attractions
Michael Thurston, general manager of Destination North Coast NSW, said that with the state's residents now free to travel, they were expecting a very busy summer on the North Coast, with many venues at capacity.
"With nature-based tourism being the leading driver for visitation to the North Coast, a wet summer will inevitably impact visitors experiences in our region," he said.
"Similar to most regional destinations, the North Coast has a shortage of all-weather attractions. The projected La Niña weather for the summer may be the catalyst for operators to expedite the development of new all-weather experiences and attractions."
Check for adequate insurance
Last month, insurance company QBE warned businesses to check their exposure to storm and flood in relation to potential damage to property, contents, and stock in anticipation of La Niña being declared.
“It's about being prepared and understanding your exposure, whether that relates to a private residence, or a commercial or industrial occupancy,” said Craig Rogers, QBE’s risk engineering manager.
“Find out the exposure to tropical cyclones, storms and flooding, and review if mitigation is sufficient to reduce the likelihood of property damage and interruption to business operations. Business continuity planning should also include review of exposure to weather perils.”
La Niña is part of a cycle known as the El Niño-Southern Oscillation, a naturally-occurring shift in ocean temperatures and weather patterns along the equator in the Pacific Ocean. During La Niña, waters in the central or eastern tropical Pacific become cooler than normal, persistent south-east to north-westerly winds strengthen in the tropical and equatorial Pacific, and clouds shift to the west, closer to Australia.