Illustration of high-energy atmospheric phenomena occurring in winter thunderstorms and lighting discharges in the coastal area of Japan Sea. Since 2015, the GROWTH (Gamma-Ray Observation of Winter Thunderclouds) collaboration has been building a new multi-point radiation observation network. The group has already detected photonuclear reactions triggered by a downward terrestrial gamma-ray flash associated a lightning discharge (e.g., Enoto et al. Nature, 2017) and gamma-ray glow from winter thunderstorm (e.g., Wada et al. GRL 2018). This project is aiming to collaborate with measurements of atmospheric electric fields and with radio observations of lightning discharges.