A study is made of the structure of supercell hailstorms, the featuresof vertical air flow and its behavior of propagation in terms of 3 radar observations and an in-cloud ridaosonde one. For the weather conditions associated in the supercell hailstorms, emphasis is laidupon the analyses of the effects on the cloud both of vertical shear of ambient winds and of the precipitational process before the hailstorms.The problem of supercell modification is also discussed.