THE CLIMATE KELPIE BLOG: What’s with the rain and is there more to come?

Posted by BCG on 29th March 2022

What’s with all the rain? Two La Nina’s in a row is pretty unlikely right? Wrong. It’s actually not uncommon for a La Niña to occur in two consecutive years. In fact, since 1958, about half of La Niña events reoccurred the following year. But three in a row, now that’s very, very unlikely! Since 1950, three consecutive La Niña’s have occurred only twice: 1973 – 75 and 1998 – 2000.  

But it’s not just the central and eastern tropical Pacific Ocean becoming cooler than normal (a La Niña) this year that’s driving such wet conditions. The autumn floods experienced across much of Australia’s eastern seaboard has been exacerbated or preconditioned by high rainfalls and wet conditions from last year as well as the convergence of negative Indian Ocean Dipole (IOD) and positive Southern Annular Mode (SAM) with La Niña. When these three actors conspire, the amount of moisture evaporated from the nearby seas is higher and rainfall can be extreme in Australia’s east. Now we’re talking unusual, aren’t we?  

Keen to know more? 

Read Andréa S. Taschetto (Associate Professor, UNSW Sydney) and Agus Santoso’s (Senior Research Associate, UNSW Sydney) article Back so soon, La Nina? Here’s why we’re copping two soggy summers in a row  

Read Chiara Holgate, Agus Santoso and Alex Sen Gupta’s article: The east coast rain seems endless. Where on Earth is all the water coming from?  

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