The purpose of research is the study of the transformation of the shock-wave configuration, caused by the reflection of a spherical shock wave from a flat surface. The blast of HE charge heightened over earth surface leads to formation of shock-wave triple configuration. In spite of static pressure equality of gas streams after the different wave sequences, the velocities, densities and other flow parameters are not equal. In view of the fact that flow velocities are sufficiently different, wind loads on objects subjected to blast wave action differ also. So blast shock wave hazard degree (in particular, for human organism at body translation) depends on both object and HE charge blast height. The mathematical model to calculate and analyze the propagating shock-wave triple configurations occurring at the heightened blast is provided in this study. The model is useful for calculation and comparison of the velocities and dynamic pressures of the streams behind the different sequences of shock waves in the triple configuration, i.e., it allows us to estimate the basic parameters characterizing the tertiary blast wave hazards.