Pluvial

Pluvial is an adjective meaning related to rain or rainfall. It derives from the Latin pluvia, rain. In earth sciences, the term is used to describe a period or conditions characterized by above-average rainfall in a region, often leading to expanded lakes, rivers, and vegetation. A pluvial period is a humid interval during which precipitation patterns shift, sometimes in connection with larger climate cycles such as glacial–interglacial changes. The term also applies to pluvial lakes, which form in arid or semiarid basins during humid spells when rainfall and runoff accumulate; many of these lakes disappear when the climate becomes drier.

In contemporary hydrology and flood management, pluvial is used to distinguish rain-driven processes from coastal or fluvial ones; for example, a pluvial flood results from intense rainfall overwhelming drainage systems rather than sealevel rise or river overflow.

Geographically, documented pluvial conditions occurred during various times in the late Pleistocene and early Holocene in parts of North Africa, the Sahel, and the western United States. Notable examples include the Great Basin pluvial lakes, such as Lake Bonneville and Lake Lahontan, which formed during transitions around the last glacial–interglacial period; in Africa, the African Humid Period expanded lakes and vegetation across the Sahara and supported a greener Sahel.

See also interpluvial, pluvial lake, and humid period. The term is primarily used in geology, climatology, and historical geography to describe humidity-driven changes rather than current weather events.