Castle Bravo
The decision to carry out the Bravo test under the prevailing winds was made by Dr. Alvin C. Graves, the Scientific Director of Operation Castle. Graves had total authority over detonating the weapon, above that of the military commander of Operation Castle. Graves appears in the widely available film of the earlier 1952 test "Ivy Mike", which examines the last-minute fallout decisions. The narrator, the western actor Reed Hadley, is filmed aboard the control ship in that film, showing the final conference. Hadley points out that 20,000 people live in the potential area of the fallout. He asks the control panel scientist if the test can be aborted and is told "yes", but it would ruin all their preparations in setting up timed measuring instruments. In Mike, the fallout correctly landed north of the inhabited area but, in the 1954 Bravo test, there was a large amount of wind shear, and the wind that was blowing north the day before the test steadily veered towards the east.
Duck and cover
A notable comparison to underline this is found when one compares the 50 megaton air-burst Tsar Bomba, which produced no concentrated local/early fallout, and thus no known deaths from radiation, with the surface burst of the 15 megaton Castle Bravo, which in comparison, due to the local fallout produced, was implicated in the death of 1 of 23 crew on the Lucky Dragon and made the entire Bikini Atoll unfit for further nuclear testing until enough time elapsed and the intensity of the radiation field had decayed to acceptable levels.
Furthermore, regardless of if a nuclear attack on a city is of the surface or air-burst variety or a mixture of both, the advice to shelter in place, in the interior of well-built homes, or if available, fallout shelters, as suggested in the film "Duck and Cover", will drastically reduce one's chance of absorbing a hazardous dose of radiation. A real-world example of this occurred after the Castle Bravo test where, in contrast to the crew of the Lucky Dragon, the firing crew that triggered the explosion safely sheltered in their firing station until after a number of hours had passed and the radiation levels outside fell to dose rate levels safe enough for an evacuation to be considered. The comparative safety experienced by the Castle Bravo firing crew served as a proof of concept to civil defense personnel that shelter in place (or "buttoning up" as it was known then) is an effective strategy in mitigating the potentially serious health effects of local fallout.