ELECTRIC FIELD INTENSITY AT THE GROUND UNDER ACTIVE THUNDERSTORMS AND TORNADOES

Abstract

Electric field intensity-measurements were made at eight stations near the 25 May 1955 tornado which devastated Udall, Kansas. Simultaneous records are reproduced, showing the electrical activity throughout the near passage of this tornado funnel. This storm systematically transferred or induced positive electrical charges on the ground which were neutralized in part or over-neutralized by lightning discharges. The records show that the storm was very active, and wide excursions in the magnitude and sign of the electric field were observed. At the time of passage of the funnel near one observing station, the surface electric-field fluctuations became relatively quite small and the electric field intensity approximated +40 volts/cm. There is little evidence suggesting that the electrical effects near the funnel differ basically from ordinary thunderstorm electrification.