Concatenated Hazards: Tsunamis, Climate Change, Tropical Cyclones and Floods

Abstract

Concatenated Hazards refers to situations where one extreme event precipitates one or more other extreme events. The exemplar is the tsunami and the resulting nuclear accident that occurred in Japan following the 11 March 2011 magnitude 9 earthquake.Australia’s major natural hazards are hydro-meteorological in nature and have resulted in concatenated hazard events. An example is the 2011 Cyclone Yasi. The rainfall in the Australian tropics is due to the effects of the monsoonal wet season, augmented by the extra rainfall from the occasional tropical cyclone. Though tropical cyclones themselves can produce strong winds, storm surges, and floods – the combination of a particularly wet wet-season and a tropical cyclone can intensify the disaster and amplify the consequences. This was the situation on 3 February 2011 when Cyclone Yasi made landfall in North Queensland, following on a December-January period that had seen extensive flooding in Queensland as a result of a strong La Nina. The extra concatenation from Tropical Cyclone Yasi was the increase in Australian banana prices.The predictive ocean–atmosphere model (POAMA) of the Centre for Australian Weather and Climate Research indicated in May 2010 that the wet season in Queensland would be extensive, with large amounts of rainfall. Tropical cyclone Yasi, though intense, had a well-behaved track and from 30 January was forecast to make landfall in Northern Queensland.Model results indicate that the effects of climate change will be to decrease the numbers of tropical cyclones affecting Northern Australia and to increase the proportion of severe tropical cyclones affecting the region.KeywordsConcatenated hazardsNatural hazardsClimate changeFloodsTropical cyclonesTsunami