Definition of "Cascade" :

noun: a sudden downpour (as of tears or sparks etc) likened to a rain shower

"A sudden cascade of sparks."

noun: a succession of stages or operations or processes or units

"Progressing in severity as though a cascade of genetic damage was occurring."

noun: a small waterfall or series of small waterfalls

verb: arrange (open windows) on a computer desktop so that they overlap each other, with the title bars visible

verb: rush down in big quantities, like a cascade