Lessons learned from flash floods early warning system in a mountainous rur-urban region of Colombia

Abstract

The city of Manizales, Colombia, located in the tropical Andes, faces recurrent hydroclimatological risks due to its mountainous terrain, high rainfall variability, and urban expansion into vulnerable areas. This article presents the evolution of different Early Warning System (EWS) into a Multi-Hazard Early Warning Systems (MHEWS), based on the United Nations' framework for disaster risk reduction. The transition was enabled through the integration of real-time hydroclimatic monitoring, development of tailored rainfall and river level indicators, and collaborative governance involving academia, communities and local authorities. Key indicators such as A25, A10_min, P10Level, and i_med have enhanced predictive capacity, though limited historical event data constrain full validation and efficiency assessment. Lessons learned emphasize the importance of adapting international alert protocols to local dynamics, improving real-time data coverage, and strengthening community participation. The study also highlights institutional and governance challenges, including short lead times, limited forecasting tools, and the absence of comprehensive disaster databases. Despite these limitations, the Manizales case demonstrates that localized innovation, institutional collaboration, and risk aware culture can drive the effective development of MHEWS in low- and middle-income mountainous regions. This experience offers transferable insights for similarly exposed cities across the tropics.