Operation Tumbler-Snapper was a series of atmospheric nuclear tests carried out at the Nevada Proving Grounds by the U.S. Government. The full series consisted of 8 detonations, or 'shots' in the parlance of the industry. The shots were designated using phoenetic alphabetics, so Shot Able, Shot Baker, Shot Charlie, etc. etc. All eight took place between April 1, 1952 (no foolin') and June 5, 1952.

Approximately 10,600 personnel from various branches of the DoD were involved. The code name for the test series is in two parts to signify that there were two overlapping series of tests, each serving a different 'master.' The Tumbler test series, which consisted of shots Able through Dog, were all air-dropped weapons. Data from these explosions were of primary importance to the Department of Defense, which was interested in the effects of nuclear weapons - both on ground targets, as well as on friendly forces and combat operations. Shots Charlie and Dog were also instrumented for the Atomic Energy Commission and the Los Alamos National Laboratory in order to collect information on detonation phenomena for use in designing nuclear weapons themselves. They were also considered part of the Snapper series. Shots Echo through How were all tower shots - the devices were placed atop fixed towers, just like at Trinity. These tests were purely part of Snapper.

During shots Charlie, Dog, and George, units of the Sixth Army carried out tactical maneuvers in close proximity to the detonations in order to test both their tactics and the equipment. These were dubbed Exercise Desert Rock IV. Psychological testing was carried out during the Charlie, Fox and George shots to determine the effects of the detonations on trained ground troops.

The yields of the various shots were as follows, according to the U.S. DOD fact sheets on the test:

  • Shot Able: 1 Kt, airdropped over Frenchman Flat on 1 April.
  • Shot Baker: 1 Kt, airdropped over Yucca Flat on 15 April.
  • Shot Charlie: 31 Kt, airdropped over Yucca Flat on 22 April.
  • Shot Dog: 19 Kt, airdropped over Yucca Flat on 1 May.
  • Shot Easy: 12 Kt, tower detonation at Yucca Flat on 7 May.
  • Shot Fox: 11 Kt, tower detonation at Yucca Flat on 25 May.
  • Shot George: 15 Kt, tower detonation at Yucca Flat on 1 June.
  • Shot How: 14 Kt, tower detonation at Yucca Flat on 5 June.
Note that Yucca Flat had, at this point, at least seven distinct testing areas. Some were re-used during this sequence.

Personnel were exposed to radiation during this test. Later, by 1982, the U.S. Military had identified just over 5,000 personnel who had taken part in this test, as well as film badge dosimeter information that could be correlated to 1800 or so of them. Of those, 42 had exceeded the joint AEC/DOD 3-roentgen limit, and eight had exceeded a higher 3.9 roentgen limit that their various organizations had had in place.


  • Defense Nuclear Agency: "Operation Tumbler-Snapper: United States Atmospheric Nuclear Weapons Tests - Nuclear Test Personnel Review." Document# DNA1.940923-067 / DNA6019F, Defense Nuclear Agency for the U.S. DOD, 1952.
  • Personal Chronicle of Clark Caldwell, U.S. Atomic Veterans, at http://www.aracnet.com/~pdxavets/caldwec.htm
  • Defense Threat Reduction Agency: "DTRA Fact Sheet: Operation Tumbler-Snapper", http://www.dtra.mil/press_resources/fact_sheets/display.cfm?fs=ntpr_tumbsnap