This is the second year in a row of a negative IOD, which refers to the patterns of sea surface temperature. While positive dipoles are associated with dry weather, negative dipoles can bring heavy rainfall and flooding to parts of Australia.

The NSW SES said it is particularly concerned for the Hawkesbury, Nepean and Georges rivers, Northern Rivers, Mid North Coast, Central Coast and Shoalhaven catchment. The agency is preparing its units for future flooding events.

The agency has just experienced its biggest year on record. Between June 1 and August 3 this year, NSW SES members responded to 13,390 weather-related requests for assistance across NSW.

NSW SES Commissioner Carlene York said the third La Nina event presented a set of unique risks and challenges to the community, especially for those that had already undergone flooding events earlier this year.

Since the February and March floods, more than 1300 new members have undergone training, while more than 2077 applications are being assessed.

While La Nina causes warmer-than-average sea temperatures off Australia’s coast, which drive storms, it cools down ocean temperatures in the Northern Hemisphere, which creates drier onshore weather. The west coast of the US is experiencing its longest dry spell in 1200 years, while cities across the country’s west are grappling with how they manage dwindling water supplies.

In California, the statewide snowpack was just 38 per cent of the average as officials grow more concerned for the coming wildfire season.

Climate change continues to influence Australian and global climate. The country’s climate has warmed by 1.47 degrees between 1910 and 2020. In southern Australia, there has been a reduction of 10 to 20 per cent in the cool season rainfall, while in other parts of the country there has been a shift towards higher intensity rainfall over shorter periods of time.

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