What is a key characteristic of a flood?

A key characteristic of a flood is sudden and significant rainfall. Flooding typically occurs when there is an excessive amount of rainfall over a short period, causing rivers, lakes, and streams to exceed their capacity and overflow onto adjacent land. This rapid accumulation of water leads to inundation, which can severely impact communities, agriculture, and infrastructure.

While an imbalance in rainfall can lead to other issues, such as drought (which relates to choices A and C), these conditions do not characterize a flood. Controlled water levels (choice D) suggest a management situation where water is regulated effectively to prevent flooding, which is the opposite of what happens during a flood event. Therefore, the most accurate description of a flood is that it results from sudden and significant rainfall, causing immediate and often widespread water overflow.