PLUVIAL

(1) Of having to do with rain; rainy. (2) To flow, pour, or fill. (3) (Geology) Formed or caused by the action of rain, as a pluvial deposit. (4) (Geology) More specifically, the two or more Wisconsin stages, of the late Pleistocene age (epoch), when the western United States waterbasins were filled with lakes. The Early Pluvial period consisted of periods of high humidity so remote as to have left no clear-cut shore features; the Postpluvial period represented a period of desiccation following the last high lake stage.