Duck and Cover - Assessment

Assessment

Within a considerable radius 0–3 km—largely depending on the explosion's height and yield—ducking and covering would offer negligible protection against the intense heat, shock wave, and radiation following a nuclear explosion. Beyond that range however many lives would be saved by following the simple advice, especially since at that range the main danger is from sustaining burns to unprotected skin. Furthermore as the explosion's blast wave would take 9 to 10 seconds to reach a person standing 3 km from an explosion, the exact time of arrival being dependent on the speed of sound in air in their area, there would be more than ample amounts of time to take the prompt countermeasure of 'duck and cover' against the blast's direct effects and flying debris.

The advice to "duck and cover" holds well in many situations where structural destabilization or debris may be expected, such as during an earthquake or tornado. At a sufficient distance from a nuclear explosion, the blast wave would produce similar results and ducking and covering would perhaps prove adequate. It would also offer some protection from flying glass and other small, but dangerous, debris. Ducking and covering would also reduce exposure to the gamma rays. Since they are mostly emitted in a straight line, people on the ground will have more chance to have obstacles such as building foundations, cars, etc. between them and the source of radiation. The technique offers a small protection against fallout—people standing up could receive a large, possibly lethal, dose of radiation, while people protected will receive less of it. However it must be said that the technique assumes that after the initial blast, a person who ducks and covers will realise it wise to cease ducking and covering, as the blast danger has passed, and to then seek out a more sheltered area to protect themselves from the ensuing local fallout danger. It is after all, a first response countermeasure only. In much the same way that 'Drop, Cover and Hold On' is during an earthquake, with the advice having little utility once the earthquake has passed, and possibly other looming dangers like a tsunami may be approaching.

In the era the advice was originally given, the most common nuclear weapons were weapons comparable to the Fat Man. The main dangers that initially come from the nuclear blast from weapons of this, and higher, yields are the initial heat and blast effects and not from fallout or radiation. To maximize building damage, an air-burst is the preferred nuclear fuzing height, which maximizes surface damage and results in fallout being dispersed into the stratosphere, instead of highly contaminating the area under the explosion. For example in the Operation Crossroads tests of 1946, Test Able (an air burst) had little local fallout, but the infamous Test Baker (an underwater burst) left the test targets badly contaminated with radioactive fallout.

Widespread radioactive fallout itself was not recognized as a threat amongst the public at large before 1954, until the widely publicized story of the 15 megaton surface burst of test shot Castle Bravo on the Marshall Islands occurred with fatal results. The explosive yield of the Castle Bravo device was unexpectedly high, and therefore the correspondingly far higher amounts of fallout produced, resulted in the accidental sickness and death of one of the members of a Japanese fishing boat known as the Lucky Dragon far outside the planned test area.

It is however unlikely that a belligerent with Nuclear weapons would waste their weapons with fusing to explode below or on the surface, as both test shot Baker, and Castle Bravo were respectively. Instead, to maximise the range of blast destruction, an air burst is preferred, as the ~ 500 m explosion heights of the only nuclear weapons used on cities Little Boy and Fat man also attests to. With air bursts the total amount of radiation contained in the fallout, in units of Becquerel is somewhat less than the total that would be released from a surface or subsurface burst, as in comparison little to no neutron activation of soil occurs from air bursts. Therefore the initial danger from concentrated local fallout as was experienced by the crew of the Lucky Dragon remains low in a global nuclear War sceneraio. Instead the fallout likely to be encountered by most survivors is expected to be the less dangerous global fallout.

A notable comparison to underline this is found when one compares the 50 megaton airburst Tsar bomba, which produced no concentrated local 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, killed one of the 23 strong crew of the Lucky Dragon.

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 (film), will drastically reduce ones 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 levels safe enough to travel in.

Again to highlight the effect that being indoors can make, despite the lethal radiation & blast zone extending well past her position at Hiroshima, Akiko Takakura survived the effects of the 16 kt atomic bomb at a distance of 300 meters from the hypocenter, with only minor injuries, due in most part to her position of residing in the lobby of the bank of Japan, a reinforced concrete building, at the time of the Nuclear explosion. In contrast, the unknown person sitting outside, fully exposed, on the steps of the Sumitomo bank, next door to the bank of Japan, received lethal third degree burns and was then likely killed by the blast, in that order, within 2 seconds.

Historians have thus far sought to dismiss civil defence advice as mere propaganda. Despite detailed scientific research programmes laying behind the much-mocked UK government civil defence pamphlets of the 1950s and 1960s, including the prompt advice of Ducking and Covering.

The exercises of civil defense are seen by Historian Guy Oakes as having less practical use than psychological use: to keep the danger of nuclear war high on the public mind, while also attempting to assure the American people that something could be done to defend against nuclear attack.

In U.S. Army basic training in the 1970s, soldiers were taught to fall immediately down, covering face and hands and using their bodies to shield their weapons from the heat of the blast.

Ducking and covering does have certain applications in other, more natural disasters. In states prone to tornadoes, school children are urged to 'duck and cover' against a solid inner wall of a school, if time does not permit seeking better shelter—such as a storm cellar—during a tornado warning. The tactic is also widely practiced in schools in states along the West Coast of the United States, where earthquakes are commonplace. Ducking and covering in either scenario would theoretically afford significant protection from falling or flying debris.