Since national rainfall records began in 1900, 2010 was Australia’s third wettest year, with 2011 coming in second. It rained an average of 703 millimetres in 2010 and 708 millimetres in 2011 over Australia, much higher than the long-term normal of 465 millimetres.
The only year with more precipitation (760 mm) was 1974, dominated by one of the strongest La Nia episodes on record. The Murray-Darling Basin and Queensland both experienced their wettest years on record in 2010, while Western Australia experienced their wettest year ever in 2011.
From July 2010 through March 2011,
Most of Australia saw far more precipitation than usual due to La Nia. Some of Tasmania also saw record rainfall, but amazingly, the southwest of Western Australia had the driest year on record. Australia experienced its wettest September, December, and March on record and its second- and third-wettest October and February, respectively. Northern Australia experienced the wettest ‘dry’ season on record from May to October 2010. The southern part of the country experienced its wettest second half of the year from July to December of 2010 than ever before or after.
Victoria saw its wettest summer on record, while Western Australia and the rest of Australia experienced the second-wettest summers. The wetter spring was a national record for Australia and all States except Victoria and Tasmania as stated by The Australia Time.
The long-term and severe drought that had plagued the Murray–Darling Basin was finally broken by the La Nia event that occurred in 2010–11. Queensland, New South Wales, and South Australia saw substantial water storage capacities increase due to recent heavy rains. There was a 20% increase in the amount of water retained in the United States’ largest publicly owned storage Between May 2010-2011.
From October 2011 to March 2012,
Most of mainland Australia experienced above-average rainfall due to La Nia. However, this was not as extreme as the 2010-11 events. Despite this, several records for precipitation were set: the second wettest November and spring in Western Australia’s history and the second wettest March in New South Wales’ history.
Australia saw its wettest two-year period (April 2010–March 2012) and wettest 24-month period (April 2010–March 2012) ever as a result of the two catastrophes (2010–2012). The 1411 mm of rain that fell in the 2010-2011 season was more than the 1407 mm that fell in the 1973-1974 season.