Despite lightning and thunderstorms being a rather common phenomenon, the underlying physics is still not well understood. It remains an enigma how lightning strikes are initiated at electrical field strength well below the break-through voltages needed in the lab to create a spark. Just recently another high-energy phenomenon in the atmosphere has been found. It is the acceleration of electrons in the strong electric fields of the thunderclouds. As a consequence, increased fluxes of electrons, gamma rays and neutrons can be detected on the earth’s surface, in the atmosphere and in space. Such high-energy particle fluxes are often accompanied by disturbances of the near-surface electric field, by high-frequency radio emissions, extensive air showers and impressive lightning discharges. A number of experiments record all these features simultaneously, together with relevant meteorological parameters. The combined analysis of these parameters and ... More on LEAD-2015_English.pdf