Using a digital high-speed microscopic video recording technique developed in our laboratory, we have investigated high-temperature combustion synthesis waves in the Ni + Al system. Based on the results obtained, we identify characteristic features of rapid high-temperature reaction wave propagation in heterogeneous media. It is shown that, while at time scales similar to 10(-1)s the reaction wave propagation appears to be steady, at time scales similar to 10(-3) s it exhibits features of hesitations followed by jumps, and at even faster time scales similar to 10(-4) s is shown to follow a novel scintillating reaction wave mechanism.