Green’s Dictionary of Slang

(US black) trousers considered to be too short.

1974

H.L. Foster Playin’ the Dozens 186: A youngster makes fun of someone's pants by teasing him about the length of the trousers. This may take the form of referring to someone's pants as Pacific Oceans, floods, or high waters. [. . . .] The implication is that the pants are too short for the youngster's height.