87th AMS Annual Meeting

Monday, 15 January 2007
On the mechanisms resulting in post-fire flash floods: a case study
Exhibit Hall C (Henry B. Gonzalez Convention Center)
Lee Tryhorn, Monash University, Clayton, Vic., Australia; and A. Lynch and R. Abramson
Vulnerability to the impact of climate change depends on both the nature and extent of the impact and how communities can respond. With improved information and strategies it is possible for communities to prepare for potentially abrupt changes in climate state or variability. Using the theoretical tools of the policy sciences, this study focuses on priorities identified by the residents of the Alpine Shire, an area in northern Victoria that has borne the brunt of many extreme events in recent years. Characteristics of the regional climate have a great influence on the local economy and agriculture.

The community has recognized a vulnerability to fires and post-fire floods. Bushfires can have severe consequences for many components of forest ecosystems, from the destruction of vegetation to the changing of soil structure and properties. Soil after fire becomes hydrophobic and flooding may occur because of a drought break or localized thunderstorms.

The start of 2003 saw large areas of southeastern Australia ravaged by fire. 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 localized flash flooding. An analysis of the meteorological conditions leading to this extreme rainfall in Alpine Shire, Victoria 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 study will assist in emergency preparedness in the Alpine Shire.

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