a large amount of rain that falls quickly
Origin and usage
As a compound noun, downpour is a combination of ‘down’ from the Old English ‘adūn’ meaning ‘downward’ and ‘pour’, which has usage beginning in the Middle Ages from unknown origins.
The main defining feature of a downpour that separates it from rain is the severity and duration of the precipitation that occurs. The kind of clouds that generate enough rain to characterize a downpour have a greater vertical depth than typical rain clouds as well as strong air currents that rise up and down, cooling and heating the large particles of the cloud structure. In order to create a downpour, the cloud must contain a high amount of liquid water and form quickly enough so that the resulting shower dumps all the accumulated water mass at once.
The swirling updraughts and downdraughts typically take the form of a cumulus or cumulonimbus cloud, which is characterized by a cauliflower head and appears fluffy and thick. In order to dump out so much precipitation so quickly, the cloud must be tall but narrow, which is why downpours usually last a matter of minutes or hours rather than days.
“To speak little is natural. Therefore a gale does not blow a whole morning nor does a downpour last a whole day.”
“The rain continued. It was a hard rain, a perpetual rain, a sweating and steaming rain; it was a mizzle, a downpour, a fountain, a whipping at the eyes, an undertow at the ankles; it was a rain to drown all rains and the memory of rains.”
deluge, rainfall, rainstorm, shower