Debris-flow initiation is the study of the factors and processes that lead to the formation and triggering of debris flows, which are rapid and potentially dangerous mass movements of soil, rock, and water down steep slopes. Researchers in this area investigate various triggers such as heavy rainfall, snowmelt, earthquakes, or human activities, as well as the characteristics of the materials involved and the topography of the slope. Understanding debris-flow initiation is important for hazard assessment and mitigation planning in areas prone to these natural disasters.