Abstract: In the context of the increasingly severe global challenge of climate change, the frequent occurrence of extreme weather events and the intensification of human activities are becoming increasingly intertwined. Combined with the inherent vulnerabilities of engineering systems, these factors have collectively led to a significant increase in catastrophic events triggered by reservoir dam failures. This phenomenon has become a critical risk that urgently demands attention in the field of dam safety management, posing a severe threat to human life and property, social stability, and the ecological environment. This study offers an in-depth analysis of dam-break catastrophes through a systematic review of 20 typical dam-break incidents worldwide from 2018 to 2024. Dam-break catastrophes are not merely reservoir dam failures; rather, they involve a series of systemic and compound disasters precipitated by such failures. These disasters are characterized by extremely high destructive intensity, often affecting multiple geographic regions, and have severe social consequences that far exceed the typical thresholds of conventional dam-break accidents. From the perspective of driving mechanisms, dam-break catastrophes result from the multiple coupling effects of extreme loads – engineering defects – management failures. Extreme loads—such as extraordinary floods and glacial lake outburst floods—exert immense pressure on reservoir dams; engineering defects—including flawed design, poor construction quality, and age-related deterioration—weaken the structural resilience of dams; and management failures—such as delayed monitoring and warning, and inadequate emergency response—further intensify the disaster’s severity. These factors interact and reinforce one another, ultimately leading to dam-break catastrophes. In terms of disaster characteristics, dam-break catastrophes display a series of critical features, including mass-scale casualties – infrastructure collapse – breakdown of social functions – cross-border secondary disasters. Mass-scale casualties involve large numbers of deaths or missing persons, inflicting devastating losses on affected families. Infrastructure collapse paralyzes transportation, communication, water supply, power systems, and other essential services, severely disrupting daily life and production. The breakdown of social functions leads to disorder in public life, impairing the government's ability to maintain order and deliver services. Cross-border secondary disasters can trigger cascading effects—such as flooding, landslides, and environmental pollution—further amplifying the disaster’s scope and impact. Based on disaster loss assessment theory and threshold analysis methods, this study develops a disaster loss index model and a catastrophe classification model across three dimensions: life loss, economic loss, and social loss. This model comprehensively accounts for damages across these dimensions in dam-break catastrophe events, offering a scientific basis for accurately assessing disaster severity and determining catastrophe levels through quantitative analysis. Through detailed examination of typical cases, the findings indicate that the consecutive failures of two reservoirs in Derna, Libya, resulted in a high number of fatalities and missing persons, with the life loss index reaching an extreme level. The glacial lake outburst flood impacting the Teesta III Hydropower Project in India caused substantial economic losses, with the economic loss index particularly prominent. The dam failure at the Xe-Pian Xe-Namnoy Hydropower Project in Laos led to a complete breakdown of social functions, with the social loss index proving especially significant. In all three cases, the disaster loss indices exceeded the established thresholds for dam-break catastrophes, fully validating the model’s effectiveness and reliability. The study recommends progressively establishing a climate-adaptive reservoir dam engineering resilience system, with an emphasis on dynamic risk assessment of high-risk reservoirs, life-cycle risk management, and the application of technologies such as digital twin-based monitoring and early warning systems. These measures aim to promote a shift in safety management from passive defense to proactive adaptation, providing critical support for decision-making support for addressing dam-break catastrophe risks under climate change.