Flash floods are sudden and intense floods that occur within a short period, usually within a few minutes to six hours after heavy rainfall, cloudbursts, dam failures, glacial lake outburst floods (GLOFs), or rapid snowmelt. Unlike river floods that develop gradually, flash floods occur with little or no warning, making them one of the most dangerous hydro-meteorological disasters. Their high velocity and destructive force often result in significant loss of life, damage to infrastructure, disruption of livelihoods, and environmental degradation. Flash floods are caused by both natural and human-induced factors. Intense and localized rainfall, cloudbursts in mountainous regions, cyclones, and thunderstorms are the primary natural causes. In the Himalayan region, glacial lake outburst floods caused by melting glaciers due to climate change have become an increasing concern. Human activities such as deforestation, unplanned urbanization, encroachment on natural drainage channels, poor land-use planning, construction on floodplains, mining, and inadequate drainage systems further aggravate the occurrence and severity of flash floods. Flash floods possess several distinct characteristics. They develop rapidly with little lead time, often catching communities unprepared. Water levels rise suddenly and flow at extremely high speeds, carrying debris, rocks, mud, and uprooted trees. They usually affect small catchments, steep valleys, urban areas, and low-lying regions where water