A La Nina weather event is expected to run from next month until at least the end of the year and a negative Indian Ocean Dipole (IOD) could also develop, the Bureau of Meteorology warned today.

“Both La Nina and negative IOD typically increase the chance of above average rainfall across much of Australia during spring,” the bureau said.

“Above average summer rainfall is also typical for much of eastern Australia during La Nina.”

The last significant La Nina event was in 2010-11, which was Australia’s wettest two-year period on record. Devastating floods in Brisbane and other parts of Queensland resulted in insured losses of more than $1.5 billion.

Bureau background documents confirm the presence of La Nina “increases the chance of widespread flooding”.

While the bureau rating system remains unchanged at La Nina Alert, it says further cooling of the surface of the tropical Pacific Ocean is expected.

“All surveyed international climate models indicate La Nina thresholds will be met from October until at least the end of the year, with most models maintaining these values into early 2021.”