cascade
noun
°A waterfall or series of small waterfalls.
"Now murm'ring soft, now roaring in cascade. -Cawper"
°A stream or sequence of a thing or things occurring as if falling like a cascade.
"The rise in serotonin levels sets off a cascade of chemical events — Richard M. Restak, The Secret Life of the Brain, Joseph Henry Press, 2001"
verb
°To fall as a waterfall or series of small waterfalls.
°To arrange in a stepped series like a waterfall.