Meteorological Analysis of the Forcett-Dunalley Wildfire in 2013 in Tasmania, Australia
Abstract. A major bushfire occurred during January 2013 near the towns Forcett and Dunalley in southeast Tasmania, Australia. Several records were broken by this wildfire, in terms of impacts to eco-systems, infrastructure and lives, as well as the first documented fire storm development in Tasmania in the form of pyrocumulonimbus. The Australian Bureau of Meteorology high-resolution regional reanalysis for Tasmania (BARRA-TA), with 1.5-km spatial resolution, together with in-situ observations, was applied to reconstruct the wildfire event. The antecedent climatic conditions in Tasmania included large increase in fuel load due to abundant rain one to two years before the event, followed by a heatwave during the summer of 2012/13. In the three periods we identified during the event reconstruction, the second period was the most dramatic, in which a low-level jet was directed downslope in southeast Tasmania to accelerate the fire spread. Moreover, spotting of over 3 km was observed, and pyrocumulonimbus developed in this period with lightning up to 13 km from the fire. A cold front crossed the fireground during the third period, and thus played a different role compared with some past extreme fire events in terms of lifting and wind direction change. Our analyses conclude that climatic conditions, synoptic patterns and mesoscale convective environment all contributed to this wildfire event.
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