Characteristics of return strokes associated with upward lightning flashes observed in winter

In Japan, upward winter lightning frequently damages wind turbines in the coastal area of the Sea of Japan. Characteritrwapsics of current associated with such upward lightning flashes initiate from tall structures in winter are statistically quite different from ordinary downward lightning flashes observed in summer. One of the features is that return strokes associated with such upward flashes have the characteristics of subsequent strokes of downward flashes. This paper reports on characteristics of return strokes having those of subsequent strokes associated with lightning flashes observed at wind turbines in winter.