The mystery of cloud electrification

Lightning is known on occasion to transfer charge with current approaching hundreds of thousands of amperes between cloud and ground in a few microseconds, but how does this charge develop? Further, why do some cloud systems, such as this cumulonimbus over eastern Colorado, become very lightning productive, whereas other large cloud systems, such as a hurricane, produce very little lightning? The authors find that charge development in cloud systems depends on a proper mix of water and ice particles, which is in turn dependent on powerful convection.