In 1963 the Glen Canyon Dam was completed and Lake Powell began to fill. After recent, successive years of drought in the Colorado River upper basin the water level in Lake Powell has been steadily declining, and is now approximately 100 ft below the high water line. Here we present a survey of soil microbial communities at three sites in Glen Canyon, each spanning a transect from just below the current water level to above the high water line in steps of 10 vertical feet. Approximately 100 samples were collected, and archaeal and bacterial 16S rRNA was sequenced on the Illumina HiSeq2000 platform to a median sampling depth of approximately 81,000 sequences per sample. We show that the phylogenetic composition of the submerged and exposed soil microbial communities are distinct, and that with time since reemergence microbial communities of exposed soils have become more similar to those of biological soil crusts, which typify undisturbed soils of the area. Our results suggest that as the water level of Lake Powell recedes, the microbial communities of Glen Canyon soils are dynamically recovering from flood disturbance.