Abstract. Natural hazards have substantial impacts on economies on all scales. While the measurement of direct effects seems manageable, less is known about the dimensions of economic effects, especially on local and regional scales. The lack of standardized terminology, empirical data and methods currently hampers profound decision support. In our study of the 2005 flood event in the Federal State of Tyrol (Austria), which triggered about 264 million Euros in direct losses, we surveyed companies from all sectors of the economy to identify the drivers of economic effects. The main aim of the study was to assess the regional economic impacts on the gross regional product by the 2005 floods without macro-economic modelling techniques using bottom-up data. Using basic quantitative and qualitative methods, we established and analysed a data pool of questionnaire and interview results as well as direct loss data. Based on this empirical evidence, we estimated the decline in gross regional product in the study area at NUTS-3 level. We observed that disrupted traffic networks, for instance, had very negative effects on the regional economy. In addition, we identified economic winners of severe hazard impacts and estimated the amount of increasing economic flows (economic stimuli), based on compensation payments. Finally, the net effect can be estimated balancing the negative and positive effects of the flood event. The methods and results of this study can help to improve ex post loss estimations, and with it, ex ante methods for the cost efficiency of risk reduction measures, e.g. cost–benefit analysis. However, much effort is needed to improve the data basis on economic effects measured as a change in economic flows.