where do floods occur

Floods can occur almost anywhere there is water, including along streams, rivers, near coasts, around lakes, or down mountainsides. They typically happen when water overflows onto normally dry land, often caused by heavy rainfall, rapid snowmelt, storm surges, or dam failures. Flooding is especially common in river valleys, floodplains, low-lying areas, coastal regions, and urban zones with poor drainage. Specific regions prone to severe flooding currently include parts of the United States, East Africa, Brazil, and Afghanistan due to various climatic and geographical factors. Mountainous and steep hill areas are also susceptible due to rapid runoff that causes streams to rise quickly, and dry riverbeds in arid zones can experience sudden flash floods. Coastal flooding occurs when sea levels exceed land levels or coastal defenses are overwhelmed. Flood-prone areas are influenced by local terrain, soil conditions, vegetation, and weather phenomena such as tropical cyclones, atmospheric rivers, or specific atmospheric phenomena like the Spanish "cold drop" (DANA).