From the scholia to Homer, Iliad 15.704-5, where the headword phrase occurs (web address 1). Compare also Homer, Odyssey 12.182, 15.473; Sophocles, Ajax 710; Moschus 2.60. Same glossing in ps.-Herodian and, according to Adler, the Ambrosian Lexicon; similar in Hesychius.
Although the adjective w)ku/alos strictly means "sea-swift, speeding over the sea" (if -alos is from a(/ls: see LSJ s.v., web address 2), later writers could apply it to swiftness or violence in other contexts: so Oppian, Halieutica 2.535, and already Pindar, Parthenia 2.19.