Winter lightning triggered by wind-turbines: the case of snowstorm Filomena

Abstract

Winter storm Filomena battered the Iberian Peninsula on the 9-10th January 2021, covering the eastern half of Spain with a huge amount of snow. Apart from the historical snowfall, lightning activity was observed during this snowstorm episode. Although most of lightning was oversea, lightning hotspots were observed in different regions across the Iberian Peninsula, such as Galicia, Asturias, Catalunya and Andalucía. A closer look at the inland lightning hotspots showed wind turbines in the close vicinity of most of the lightning. The analysis of the ERA5 variables has shown that environmental conditions were prone to winter lightning. One of the most representative is the height of the -10 °C isotherm, a key variable for cloud electrification. A low height of the -10 °C enhances electric fields at the top of tall man-made structures, like the wind turbines, favouring the inception of upward lightning. Moreover, moving blades are exposed to stronger local electric fields than static objects, favouring the initiation of stable lightning leaders and subsequent lightning strokes.

Peer Reviewed

Postprint (published version)