Thunderstorms: Lightning: What is Electrical Discharge?
Lightning occurs in thunderstorms when thunderstorm clouds reach their electrical potential. As defined by the National Oceanic and Atmospheric Administration (NOAA, 2017), “Lightning is a sudden electrostatic discharge that occurs typically during a thunderstorm.” This discharge is created when a ‘step leader’ approaches from the thundercloud, and electrons begin to flow toward the surface of the Earth (Physics World, 2018). Step leader refers to an ionized channel that is moving downward from the cloud, and creating a pathway for electrons. This path is referred to as the ‘leader channel’. A dart leader can move in steps from the cloud to ground once the leader channel has been established. A dart leader, an electrical discharge with a greater strength that moves faster along the same path as the step leader, is stronger than the others. Once the dart leader has reached the ground, it will connect the clouds and ground. A powerful electric current will flow from the cloud into the ground. This causes a flash of visible light. This is lightning, according to the NOAA 2017