When Stravinsky composed The Flood in 1961–2, he was already an experienced practitioner of serialism. It is undeniably noteworthy, then, that compositional documents for the work include two diatonic sketches, presumably the earliest versions of a passage from the Prelude. Later serial versions of the passage, which differ significantly from the diatonic sketches, nonetheless retain numerous important features introduced at that initial stage. The existence of the diatonic sketches suggests that even late in his career, Stravinsky harboured diatonic and tonal impulses. Taking into account the audible results of these impulses will contribute substantially to an understanding of his last works.