The 2003 Australian bushfires: A case study

The past two centuries have seen climate changes of a similar magnitude to those usually seen over several thousand years, with significant warming occurring on a global scale. Despite the international focus on mitigation of anthropogenic climate change, this change is now inevitable. A major concern with a changing climate is that an increase in the frequency and magnitude of extreme weather events will occur. Increases in extremes, including heat waves, droughts and severe storms, have already been documented in many parts of the world, including Australia. With improved information and strategies it is possible for communities to prepare for potentially abrupt changes in climate state or variability.

The diversity of the Australian climate means that some extremes will have importance for some communities and not others. Hence, context is crucial and this may be addressed using a detailed case study. The Alpine Shire, in northern Victoria, is one region that has borne the brunt of many extreme events in recent years. Fire, flood, drought, windstorms, reduced snowpack, and severe frosts have all been experienced in the area. Characteristics of the regional climate have a great influence on local economy and agriculture. Identifying their own vulnerability, the Alpine Shire Council has recently joined Local Governments for Sustainability, and are now working with us on a detailed, specific climate change impact assessment for the shire.

The 2003 bushfires were an event that had a huge impact on the Alpine Shire, economically, socially and environmentally. The fires were preceded by several years of below average rainfall and began with lightning strikes associated with thunderstorm activity. The fires burnt over a period of nearly 60 days and were immediately followed by storms and localised flash flooding. An analysis of the meteorological conditions leading to this extreme rainfall in Alpine Shire was performed using the PSU/NCAR (Pennsylvania State University/National Center for Atmospheric Research) mesoscale model, MM5. It is intended that the mechanisms elucidated in this case study will assist in emergency preparedness in the Alpine Shire