What is the greatest amount of rainfall that falls in a storm known as?

The greatest amount of rainfall that falls during a storm is referred to as peak rainfall. This term specifically identifies the maximum intensity of rain that occurs over a short period, which can significantly influence river catchment areas, runoff rates, and flooding potential. Understanding peak rainfall is essential in hydrology and river management, as it helps predict how much water will flow into rivers and streams, therefore affecting flood risk assessments and urban planning.

The other options relate to different components of hydrological studies. Peak discharge refers to the highest flow rate of water in a river following rainfall, which occurs after the peak rainfall. Lag time is the period between the peak rainfall and the peak discharge in a river, illustrating how long it takes for rainwater to flow into the river system. A storm hydrograph is a graphical representation that shows the discharge of a river versus time following a storm, showcasing the relationship between rainfall and river response but does not specifically denote the greatest rainfall amount.