First reported detection of a winter continental gamma-ray glow in Europe

Abstract. This study presents the first-ever published detection of two parallel winter continental gamma-ray glows in Central Europe, observed during a rare winter thunderstorm on Milešovka hill, Czech Republic. The combination of the hill's altitude of 837 m above sea level (a.s.l.) and the low altitude of the winter thunderstorm cloud resulted in an observation very near the acceleration region inside the thundercloud. The event was captured using a combination of advanced instruments, including a Ka-band cloud profiler (which enabled a detailed analysis of the storm's microphysics), a SEVAN large-area scintillation detector for monitoring ionizing radiation, and a staffed professional meteorological observatory. The radar data indicated the alignment of ice crystals within the cloud, strongly suggesting the presence of a substantial electric field. The findings offer valuable insights into winter thunderstorm dynamics in continental climates, with broader implications for studying high-energy atmospheric physics.