Which type of area is most susceptible to flash flooding?

Flash flooding often occurs in urban areas due to the significant amount of pavement and buildings that prevent water absorption into the ground. This leads to rapid runoff during heavy rainfall, creating conditions ripe for flooding. Urban infrastructure, such as storm drains and sewers, can become overwhelmed, exacerbating the flooding situation.

While mountainous areas can experience flash floods due to steep terrain and rapid runoff, and coastal areas can face flooding from storm surges or tidal waves, the characteristics of urban environments make them particularly vulnerable due to their low permeability and high population density. Dry areas, although they may seem counterintuitive, can also experience flash floods after rare and intense rainfall events, but they are not typically the most susceptible when looking at overall flooding risk.