Green’s Dictionary of Slang

1. (US) the back of a horse or mule.

1864		‘Edmund Kirke’ Down in Tennessee 193: He journeys on the hurricane deck of a mule.
1885		C.A. Siringo [title] A Texas Cow Boy or Fifteen Years on the Hurricane Deck of a Spanish Pony.
1901		Illus. Bee (Omaha, Neb.) 2 June 1: [pic. caption] ‘On the Hurricane Deck’ Astride a Pitching Bronco.
1903		A. Adams Log of a Cowboy 380: McCann was transferred to the hurricane deck of a cow horse.
1916		Goodwin’s Wkly (Salt lake City, UH) 28 Oct. 4/2: Before there were any coaches; nothing but the mules’ hurricane deck on which to carry messages.
1953		Chronicle-Telegram (Elyria, OH) 29 Sept. 5/5: ‘Hurricane deck’ is a bronco’s back.

2. (Aus.) the head.

1934

C. Drew ‘Algy’ in Bulletin 8 Aug. 49/1: [O]n his hurricane deck he wore a lid that would have done credit to a corn-doctor.