After the flooding in Brisbane on 11 October I checked the Southern Oscillation Index on the BOM web-site. In September it averaged 25. Very high!
Examining previous readings since 1876 the only times this has been exceeded (note that the current reading while high is not an all-time record).
June 1900 – 26.1
April 1904 – 31.7
July 1916 – 25.7
July 1917 – 28.3
[b]August 1917 – 34.8 (WOW!)[/b]
September 1917 – 29.7
June 1950 – 26.9
November 1973 – 31.6 (followed by 1974 floods)
[color=#FF0040]September 2010 – 25.0[/color]
You can see all this presented graphically [url=http://reg.bom.gov.au/climate/current/soi2.shtml]here[/url].