September 23, 1957

The twenty-second detonation of the Plumbbob Series, an experimental device designed by Livermore Laboratory, was fired from a 500-foot tower in Yucca Flat at 5:30 a.m. today. It was code-named Whitney.

Two shots remain on the series schedule, code-named Charleston and Morgan. Unless it should develop early that on-site contamination will delay preparations for Charleston, an evaluation meeting will be held at 4:30 p.m. today to consider firing it at 5:30 a.m. PDT Tuesday, Sept. 24. A ready date has not been announced for Morgan.

There were 16 experiments connected to the sequence timer for Whitney. Seventeen aircraft flew technical and support missions. Rockets were used for cloud sampling.

Whitney was fired well before dawn, and as a result, observers at the control point saw more of the blue ionization resulting from nuclear detonation and for a longer period than is true when there is more light.

The cloud rose about 30,000 feet, with the mushroom top appearing to separate cleanly from the stem. Winds at all altitudes was close to a calm. Cloud tracking aircraft reported 35 minutes after shot time that the mushroom top was moving very slowly into due west. Much of the cloud formed from the stem was moving generally west, but one long finger was being blown due east. Because of the very low wind speeds, allowing time for radiation in the clouds to decay, and because of the considerable wind shear, diffusing the radiation over a broad area, it is anticipated that any significate fall-out will be on the test site or adjacent portions of the controlled bombing range.

Shock was felt at the control point as a soft thump, Inyokern, Bishop and St. George reported rumbles. It was not reported as heard at Sarcobatus.

[Radioactive Cloud Track]

[Operation: Plumbbob]