Revisiting a very practical and handy Rand Corporation book, "Individual Preparedness and Response to Chemical, Radiological, Nuclear, and Biological Terrorist Attacks," we can be reminded of some of the basic how-to’s involved with nuclear readiness.
To see the entire monograph in pdf form, go to: http://www.rand.org/pubs/monograph_reports/MR1731/index.html
Excerpt - Nuclear Attack
"A nuclear detonation has several immediate effects: a powerful blast that knocks over buildings, high-energy prompt radiation from the nuclear reaction, a strong flash of light and heat, and an electromagnetic pulse that may interfere with electronic equipment. The distance those effects are felt from the detonation depends on the size of the weapon and how high above the ground the detonation occurs. In the Cold War, attacks were expected to have involved many strikes with very large weapons (hundreds of kilotons). While it is not possible to predict the characteristics of future terrorist attacks, they are probably more likely to use a single smaller weapon that ranges from less than a kiloton to 10 kilotons and are likely to detonate the nuclear device on the ground, not in the air. A ground burst will have reduced blast effects but will produce a larger footprint on the ground of the highly radioactive fallout cloud, extending possibly tens of miles. This fallout could be lethal to those in its path who are not well protected. Nuclear attacks will also significantly damage infrastructure, not only to buildings but also to utilities, electronics, and other services.
"Timelines. The prompt effects of nuclear weapons are essentially instantaneous—they last for a minute or less. The fires caused by the heat from the detonation start soon after but are not likely to become a broad fire for 20 minutes or more. Radioactive particles from the fallout cloud begin to fall to the ground 10–15 minutes after the detonation near the spot of the detonation. Farther away, the radioactive fallout begins to land soon after the cloud passes overhead. After about 24 hours, all the fallout is deposited. The radioactivity in the fallout is extremely high early on. However, after two days, it will have decreased in intensity significantly (by a factor of 100 compared to one hour after the blast).
"Detection. A nuclear detonation will be unmistakable from the moment it occurs. The bright flash, the widespread physical destruction, the searing heat, and the mushroom cloud are unique. During the Cold War, the attack would have been detected as satellites tracked missiles on their 30-minute journey to the United States from Russia, which would have given individuals a chance to get to a fallout shelter. Terrorists are much more likely to deliver the weapon surreptitiously, perhaps by a truck or ship, rather than by missile. Hence, there would be little chance for early detection and warning.
"Support from Officials/Governments. Government officials would be unlikely to provide support until well after the detonation. Initial activities would include providing medical care to survivors, rescuing people from areas that are safe enough to enter briefly, and informing individuals when the fallout radiation was low enough that individuals could leave their shelters and the contaminated fallout area."
"In a surprise attack, an individual cannot avoid the initial effects of a nuclear detonation—blast, heat, and prompt radiation. However, the dangers from exposure to the radioactive fallout from the cloud that will form shortly thereafter can be reduced significantly. This will require that an individual locate the area of this radioactive cloud and act quickly. The individual’s overarching goal would be to avoid fallout by either quickly evacuating the fallout zone or seeking the best available shelter.
"1. Move out of the path of the radioactive fallout cloud as quickly as possible (less than 10 minutes when in immediate blast zone) and then find medical care immediately.
"Individuals can best protect themselves by evacuating the area where the radioactive fallout is likely to land. This is the case because evacuation provides protection that is full and indefinite and is appropriate for wherever the attack occurs and for different variations in an attack. It makes possible access to medical care, which will be critical to individuals in the blast zone who may have absorbed a high dose of prompt radiation from the detonation or sustained injuries from the blast and heat. It is also low in cost and requires little preparation. The fallout zone is defined as that area in which the fallout will generate 100 rad over 24 hours.
"Evacuation affords such protection because the onset of the radioactive fallout is not immediate but is expected to begin 10–15 minutes after the detonation in the vicinity of the blast and extend for hours as the radioactive cloud moves downwind. Thus, a shortcoming of evacuation in attacks involving chemical or radiological weapons—that it cannot be done quickly enough to provide adequate protection—does not hold in this case.
"Evacuation also protects against the hazard of large fires that may emerge in the blast zone within 20 minutes or so after the detonation and could endanger individuals in shelters.
"The distances an individual must travel to evacuate the fallout zone are not large. Even for a 10-kiloton weapon, a person located anywhere in the region between the blast site and up to about 10 kilometers (6 miles) downwind of the blast site would need to travel less than 2 kilometers (1.2 miles) to evacuate the most dangerous fallout area. Even where the radioactive cloud is at its widest, some 20 to 50 kilometers (10 to 30 miles) downwind, an individual would only need to travel at most about 5 kilometers (3 miles). In this latter case, more than 10 minutes would be available for evacuation because it would take some time for the cloud to reach that distance. Because roads are likely to be impassable for automobiles in many areas because of damage, debris, or traffic, individuals should evacuate on foot.
"The primary considerations for this action are knowing whether one is in an area that may become contaminated by radioactive fallout and, if so, knowing which direction to take. Fallout is likely to cover a portion of the blast zone. Thus, anyone in the blast zone, which will be characterized by severe damage and broken windows even at its outer periphery, is in danger of contamination from radioactive fallout. The fallout zone will extend some 20– 80 kilometers (10–50 miles) downwind, depending on the weapon’s size and the local winds. The downwind fallout zone will be less clearly delineated than the blast zone, but its approximate location can be determined by observing the mushroom cloud and the direction in which the wind seems to be blowing.
"To evacuate from the blast zone, individuals should move directly away from the blast center until they are clear. The location of the center will be apparent from the initial bright flash and subsequent vertical rise of a mushroom cloud. If the location of the detonation cannot be determined quickly, individuals should walk in the direction of less damage, where more buildings are standing and where there are fewer broken windows.
"Individuals outside the blast zone who are in the radioactive cloud path (including those who evacuated in a downwind direction from the blast zone) should move in a cross-wind direction until out from underneath the path of the developing radioactive cloud. To determine the wind direction, individuals should look for the direction that the mushroom cloud or smoke from fires is going and go perpendicular to it. If they can feel the wind, they should walk with the wind in their ears.
"Although individuals may not feel any symptoms, those in the blast zone may have absorbed a high dose of prompt radiation from the detonation. Thus, we highly recommend that such individuals receive immediate medical care once outside the fallout area because such care could be essential for survival.
"2. If it is not possible to move out of the path of the radioactive fallout cloud, take shelter as far underground as possible or if underground shelter is not available, seek shelter in upper floors of a multistory building.
If evacuation is impossible, shelter is essential for anyone remaining in the path of the radioactive fallout cloud. Radiation from local fallout can be intense, delivering a lethal dose to an unprotected person in an area up to 8 kilometers (5 miles) downwind of the detonation within an hour, depending on the size of the weapon. To protect against this radiation, individuals should get as much solid material (dirt, concrete, or masonry) and space as possible between themselves and the fallout, which collects on the ground and roofs of buildings. The best shelter is well below ground level, in the sub-basement of a building, a subway tunnel, or the lowest level of an underground garage. These shelters can reduce exposure levels by factors of 1,000 or higher.
"If an individual cannot get to an underground shelter within the timelines of the arrival of the radioactive fallout, the next best shelter would be in the upper floors of a multistory building (greater than 10 stories) but at least three stories below the roof to avoid the fallout deposited there. Protection is best as far as possible from the outside walls. Such a shelter can provide protection factors of 100 or higher, but it could be significantly less if the windows or structures have been damaged.
"Ordinary house basements provide inadequate protection in areas of intense radioactive fallout because they provide protection factors of only 10–20. However, at distances greater than about 25 kilometers (15 miles) from the detonation, where the levels of radiation will be much less, they could be sufficient. Nevertheless, because it could be difficult to know where you are in relation to the detonation and because the yield of the weapon is not known, the more shelter the better. In all cases, once inside the shelter, shut off all air circulation systems and close off doorways and windows. The room should not be sealed completely, because enough air will be needed to breathe for at least 48 hours. Individuals should remain in the shelter and await guidance from officials about when it is safe to leave, which could take 24 to 48 hours. Individuals should attempt to gain access to their emergency supply kit for use while in the shelter, but it is better to reach a good shelter in time without the kit. The ideal shelter would be prestocked with supplies to support occupants for two to three days.
"3. Find ways to cover skin, nose, and mouth, if it does not impede either evacuating the fallout zone or taking shelter.
Although radioactive fallout will not begin to land in the blast zone and surrounding areas for at least 10 minutes, some radioactive particles and dust are likely to be present from the detonation. Therefore, individuals should take the precautionary step of protecting themselves from this radiation. Respiratory protection can be achieved by using particulate filter masks or other expedient measures, such as covering the nose and mouth with clothing or towels. (See the discussion in radiological attack section.) It is important to note that, in contrast to a radiological bomb, the primary hazard from radioactive fallout is radiation absorbed from outside the body. Respiratory protection steps, therefore, will provide only limited protection. As a result, we recommend that respiratory protection be retrieved and donned but only if this causes no more than a few moments delay in evacuating the fallout zone or finding shelter.
"The radiation in nuclear fallout consists primarily of gamma emitters but also includes beta radiation. Protective clothing provides no protection from gamma radiation, although it can provide significant protection from beta radiation.
"We therefore recommend covering exposed skin but again only if it does not impede evacuating or taking shelter. In this context, any clothing that covers exposed skin and the head is considered protective clothing. Thus, most fully dressed individuals would only need a hat or hood. Protective clothing has the additional advantage of facilitating decontamination by providing a layer that can be quickly removed to dispose of any fallout material that may have accumulated on a person during evacuation or prior to sheltering.
"4. Decontaminate as soon as possible once protected from the fallout. Decontamination can provide protection for anyone who has spent time in the area of the nuclear blast or the radioactive fallout zone by eliminating exposure from radioactive particulates (dust) that have adhered to the body. Decontamination should initially focus on removing outer clothing, including shoes, and securing it in a bag or other container. Individuals should minimize contact of radioactive material with skin and eyes by rinsing exposed skin, removing contact lenses, and showering as soon as possible. Contaminated clothing should be treated or disposed of in accordance with official guidance. Decontamination should be undertaken as quickly as possible but only after an individual is protected from exposure to fallout by evacuation or sheltering.
"5. If outside the radioactive fallout area, still take shelter to avoid any residual radiation. Because uncertainty exists about exactly where the radioactive cloud will travel and where the fallout will land, it is important for individuals outside the apparent fallout zone to take shelter. House or building basements should provide sufficient protection."
One note on RAND's recommendation to evacuate if at all possible, rather than sheltering ...
If you have a well-built, well-stocked fallout shelter within easy reach, I believe reaching that protection is preferable to evacuation. Why? Because of the uncertainty of what awaits in areas where you might flee to. In my view, it's far better to take the certain safety of your shelter over the uncertain circumstances that await evacuees over the horizon.