An approximate similarity solution, derived by Raizer, of a concentrated impact (or intense explosion) at the boundary of a semi‐infinite volume of a perfect gas is used to determine the propagation velocity of the shock front as a function of its position. This velocity function is then used to obtain the shape of the propagating shock wave. It is shown that dish‐shaped shock fronts are formed when the movement of the gas at the surface is into the gas region and that cup‐shaped shock fronts are formed when the movement is out of the gas region. Comparison of these results with the shapes of explosions and meteorite craters are discussed.