Electric signals generated by tornados

Severe weather events generate electrical phenomena beyond those related to lightning discharges. In the present letter we suggest that as precipitation like rain, hail stones, and dirt move in the thunderstorm they generate an electrical signature that is characteristic for the rotation properties of the associated storm. A case study is offered which clearly demonstrates that this electrical signature is present and detectable, though it is quite weak. It can be observed that as the speed of rotation increases and diameter decreases the emitted frequency increases as would be anticipated. Comparison to synchronous radar, surface and visual data suggest that developing tornadoes in this way can be detected earlier than currently feasible weather surveillance radars. (C) 2008 Elsevier B.V. All rights reserved.