Abstract: Based on conventional observational data, civil aviation airport reports, ERA5 reanalysis data, and X-band phased array radar data, etc.observations, a winter hail event that occurred in the East China airspace on February 21, 2024, was analyzed. The results indicate that (1) This event was a typical elevated thunderstorm. An abnormally strong southwest warm and moist airflow gradually ascended above the inversion layer along a deep low-level cold cushion, creating a favorable environmental background for the development of winter elevated convective hail. The hail occurred approximately 170 km behind the surface cold front. (2) The hail was triggered by multiple instability mechanisms. Symmetric instability and convective instability were distributed at different altitudes. Conditional symmetric instability was mainly active below 700 hPa. As warm and moist air ascended along the cold dome associated with a strong frontal zone, a sloping updraft was generated. Convective instability developed in the middle layer (700 hPa and above), linking with the inclined convection induced by conditional symmetric instability in the lower layer. Under the combined influence of mid-level frontogenetic dynamic forcing, unstable energy was released and transformed into deep, intense vertical convection, enabling the severe convective storm to penetrate the −20°C level. (3) X-band phased array radar detected a thunderstorm cluster composed of supercell-like storms and multicell storms. The mesocyclone in the supercell-like storm exhibited shallow and short-lived characteristics, which enhanced convergence above the cold cushion and favored hail formation. (4) X-band dual polarization radar demonstrated significant capability in identifying winter hail. The phase evolution and growth efficiency of hail particles were closely related to the storm’s dynamic–thermal structure and microphysical coupling processes. Within the storm, differential reflectivity (Z_DR) columns and specific differential phase (K_DP) columns were both closely associated with strong updrafts. Hail embryos accumulated and grew at higher altitudes. Owing to the presence of a mid-level warm layer, dry hailstones partially melted during descent, forming wet hailstones. This process resulted in a region of elevated K_DP values and reduced correlation coefficient values in the rear flank of the storm.