Definition of "cloudburst"

[B]ut the sound . . expressed an utter abandonment to grief; not the cloud-burst of some passing emotion, but the slow down-pour of a whole heaven of sorrow.

1899, Edith Wharton, “A Cup of Cold Water”, in The Greater Inclination

A cloudburst in the China Creek district followed by continued heavy rains was responsible for the increased water.

1908, Stewart Edward White, chapter 38, in The Riverman

In Uniontown, Pa., John Walchesky & family rushed from their house when lightning set it afire, rushed in again when a cloudburst put out the blaze.

1936 August 17, “Miscellany”, in Time, retrieved 20 May 2014

[H]e walked across the lawn, wet from a fleeting late-afternoon cloudburst, the first rain in a month.

2007 Feb. 25, Norman Howard, "Devotion, chapter 1" (book excerpt), New York Times (retrieved 20 May 2014)