The greater haor basin in the northeastern part of the country covering vast area is a flash flood zone. In Bangladesh, modelling and dissemination of forecasts and warnings is much weaker for flash floods as no one organization with overall responsibility for disseminating flood forecasts and warnings to potential users. This book is an attempt to fulfill such requirement by extensive use of scientific and traditional information, providing probability information for assessment of flash flood vulnerability. It offers new opportunities to develop and implement a user-friendly, interactive decision support system for flood forecasting and identify the affected areas using dynamic modelling. The book concludes with an effective early warning system that can forecast warning in advance. It will change the existing hazard scenario and facilitate informed decision making in adopting proper measures for preparedness, mitigation, planning and management. This kind of advance warning will help the authorities for better flood preparedness and also effective mitigation.