The CSIRO’s climate adaptation unity predicts that so-called 1 in 100 year floods will become more frequent because of climate change. Within 20 years they will increase to 1 in 61 years lifting risk considerably. We need to adapt to bigger events.
There are previous years with worse floods in Brisbane (1974 1893) and heavier individual days of rain but the 6 months total rainfall for eastern Australia is unprecedented the December and January rain in Victoria is unprecedented and many other records have been set including the record low rainfall in Perth.