snowball (v.) Look up snowball at Dictionary.com
"to make snowballs," 1680s, from snowball (n.); sense of "to throw snowballs at" (someone) is from 1850. Meaning "to increase rapidly" is attested from 1929, though the image of a snowball increasing in size as it rolls along had been used since at least 1613, and a noun sense of "a pyramid scheme" is attested from 1892. Related: Snowballed; snowballing.
snowball (n.) Look up snowball at Dictionary.com
c. 1400, from snow (n.) + ball (n.1). Similar formation in West Frisian sniebal, Middle Dutch sneubal, German Schneeball, Danish snebold. Expression snowball's chance (in hell) "no chance" is recorded by 1910.