Flash floods are a particularly dangerous phenomenon that attacks and troubles people in many areas’ foothill regions. Despite water scarcity, continuous prolonged droughts and irregular rainfall in arid and semi-arid areas, recent disasters demonstrate that flooding is more severe and life threatening than ever. For example, catastrophic floods struck eastern Libya in September 2023 following the Daniel storm, resulting in more than 10,000 deaths, at least 90,000 displaced inhabitants, and millions of euros in economic damage to homes, businesses, and infrastructures. There are several factors that make arid and semi-arid regions more vulnerable to severe flooding and unexpected flood damage. On the one hand, the high variety of climate, geography, hydrogeology, and land use poses difficulties for local flood managers. On the other hand, human and system-related challenges such as lack of early warning systems, drought-based management and thorough institutional frameworks have adverse effects on Flood Risk Management (FRM). All these facts emphasize the need for a comprehensive understanding of FRM challenges in arid and semi-arid regions in order to mitigate the negative impacts of floodings on the environment, economy and society. To better understand these challenges, a case study was selected: Wadi Derna in Northeastern Libya. The current flood assessment in the basins was analyzed, and the hazards associated with the flood phenomenon were assessed for various calculated rainfall return periods. To this end, a flash flood index was calculated as a basis to understand the impact of flash floods (FF). A coupling of this index with the FF histories was included to provide a comprehensive overview of the FF vulnerability of the basin. A comprehensive method for mapping of climate and geohazards, as well as their respective impacts, has been developed by Antea Group Belgium. This includes integrating bottom-up assessments of climate vulnerability in targeted communities, models for calculating climate hazards and their impact, spatiotemporal variability of rainfall occurrence, climate change projections, and data on planned upstream dam developments. This approach enhances the accuracy and reliability of the final risk maps. Dams’ failures would be among the severe indicators of climate change; they are mirrors to our collective understanding of natural hazard risk. Dams, nowadays, cope with events that the designers never conceived, mainly in dry regions, where drought mitigation measures, including storage dams, recharge dams, artificial lakes and embankments, are implemented, while precautionary mitigation measures such as early warning systems are rare or completely missing. The analysis demonstrates that a single management strategy under climate change impacts is insufficient to reduce FF risks. To reduce vulnerability to the impacts of climate change in Libya an integrated strategy is required.