Abstract Snow‐cloud microphysics over inland hills partly resembles that over high mountains, yet exhibits notable differences. During 2024–2025 winter, coordinated observations in Tokamachi City, Niigata Prefecture, Japan, were conducted using four launches of a newly developed balloon‐borne particle‐imaging radiosonde (Rainscope) together with dual X‐band polarimetric radars deployed on both sides of Uonuma Hill (approximately 700 m ASL). Snow‐particle growth processes differed markedly depending on whether airflow passed over or was blocked by hills. Graupel formation is influenced by multiple mechanisms: advection from coastal convective clouds, orographic ascent along slopes, mountain‐wave propagation leeward of the hills, and seeder‐feeder interactions upstream. The findings demonstrate that even modest inland terrain can modulate snow‐cloud microphysics substantially, highlighting the complex role of hills in winter precipitation.
Takami et al. (Fri,) studied this question.