Sam at Oceanographers Choice has an excellent post up that seeks to address a journalist’s statement that Queensland (Australia) “should have seen the flood coming”, using a quick climatology exercise relating rainfall and the climate pattern called El Nino Southern Oscillation (currently in a strong La Nina phase) in that part of the world. In short, the answer is probably not, no; ENSO is an OK predictor at annual scales, but probably not usefully predictive at the monthly scale that would be needed to prepare a response to an anticipated flood event.
My friends in Brisbane (where I lived for 8 years during college) have all been affected directly by the flood or know someone who is. One friend rescued neighbours in a boat and another is still missing a friend in Toowoomba, west of Brisbane. The floods are getting a bit of press in the US, but perhaps not as much as they should because the body count is low (~25 compared to >600 in the concurrent Brazilian floods). That’s mostly a function of Queensland’s low population, so don’t be fooled; we’re still talking about a once-a-century or worse flood event. 75% of the state is affected, which might not sound like much until you realise that Queensland is three times the size of Texas at over 715,000 sq. miles! It is a truly gargantuan issue, especially now that there is also some flooding in Victoria and other southeasterm states. This is the equivalent of a flood that extends from Cape Hatteras to Miami and Savannah to Houston! Total cost is expected to be on the order of $10 billion, which in a state of 4.5 million is over $2,000 per person. Its staggering.
Australia truly is a land of droughts and flooding rains.