With a third La Niña officially underway, outlook shows more than 80% chance of above average rainfall

The Bureau of Meteorology has declared a La Niña event is underway in the Pacific Ocean and communities in eastern Australia should be prepared for above-average rainfall over spring and early summer.

In 2021 and 2022 La Nina rain patterns led to destructive floods across many communities in parts of south-east Queensland and New South Wales.

For communities with sodden soils, full catchments and flood damaged homes not yet repaired this is unwelcome news.

Bureau of Meteorology head of long-range forecasts, Dr Andrew Watkins, said the Bureau’s three-month climate outlook shows a high chance of above average rainfall for most of the eastern half of the Australian mainland and eastern Tasmania.

“During La Niña events, waters in the eastern tropical Pacific Ocean are cooler than normal, and waters in the western tropical Pacific Ocean warmer than normal. This causes changes in wind, cloud and pressure patterns over the Pacific.

”When this change in the atmosphere combines with changes in ocean temperature, it can influence global weather patterns and climate, including increasing rainfall over large parts of Australia”.

Flood risk remains high

While La Niña criteria have been met, most models forecast this event to be weak to moderate in strength, likely to peak during spring and ease during summer.

Other climate drivers, including the Indian Ocean Dipole and Southern Annular Mode - also in a positive phase - increases the chance of rain in New South Wales, eastern Victoria and southern parts of Queensland.

All these climate influences push Australia’s climate towards a wetter phase, and together have shaped our outlook for the coming months that shows more than 80 per cent chance of above average rainfall for many parts of the eastern half of Australia.

The Insurance Council of Australia (ICA) says now is the time to prepare property for what is forecast to be a wet spring and possibly summer.

The 2021 and 2022 combined insurance damage bill for La Nina-generated east coast storm and flooding is at $5.92 billion with more than 296,000 claims lodged.

ICA CEO Andrew Hall said: ”The last couple of years have shown the impact that heavy rains can have on property, livelihoods, and our own well-being.

”We can’t control the weather, but there are practical steps we can all take to reduce the risk that storm and flood can bring or make recovery from those events easier.”