Surviving a Nuclear Attack

I am hopeful this is information nobody will ever need. But it seems like one of those things that's better to know than not. Plus, maybe it will be a good conversation starter at your next dinner party...

Obviously, if you are too close to a nuclear explosion, you're dead. But there's an intermediate range, at which there's a lot of steps you can take to improve your chance of survival, both immediately and in the longer term. Obviously, the prepper / survivalist market has written a LOT about this, but here's my short "What To Do" immediately after a nuclear detonation. Also, please note that this is not comprehensive, nor am I an expert. Much of this is common sense, but it does include some info that surprised me when I learned it. Ultimately, you are responsible for your own safety, so try to keep calm and do what you can to stay alive.

The First Instant:  Seek cover from the flash and immediate radiation exposure - If you suddenly experience a flash brighter than the sun, DO NOT LOOK AT OR TOWARD IT. In fact, turn away from it, and get as much cover between you and the flash as possible. If the detonation is a high yield explosion, the flash may last many seconds. The flash isn't just visible light. It is intense radiation across the spectrum from long-wave thermal IR to gamma. Closer in to ground zero, the flash will ignite fabric and paper. There are photos of Japanese atomic bomb survivors with the patterns from the fabric of their clothes seared into their skin by the differential absorption of thermal radiation. Flash fire is an immediate hazard as things around you, and possibly your clothes, may burst into flames. If this happens, try to put out / remove the fire as quickly as possible, even while seeking cover.

The First 10-60 Seconds:  Seek cover from blast. Time is of the essence: If you're too close to the explosion, you won't have sufficient time to seek cover from blast effects, but then if you're that close, you may well be incinerated anyway. Try to get away from and seek cover from things that will become shrapnel when the blast wave hits, particularly glass. Windows will shatter inward and the glass shards will embed in everything they hit. In the immediate aftermath, medical care may be unavailable, and you want to try to minimize the risk of injuries that can get infected. Glass shrapnel can also be difficult to remove because it is not as easy as metal to identify in x-rays. If you get to cover, and then it seems like no blast wave comes, DO NOT LOOK OUT TO CHECK. Your sense of time may be distorted by the stress of the situation, and you don't want to stick your head out just as the blast sprays you with high speed debris. If, for some reason the blast doesn't reach you, you are still better off staying under cover anyway (see "The First Three Minutes" next.)

The First Three Minutes:  Stay shielded from the fireball. The primary nuclear reaction in a detonation is over in about the first 30 nanoseconds. However, during that initial nuclear reaction, many different radioactive materials are produced, and they continue through their radioactive decay chain. Some of the materials have very short half-lives. This means that the fireball and subsequent mushroom cloud is still emitting a great deal of ionizing radiation. The activity rate drops off over time, but staying under cover for even three minutes will significantly reduce your acute radiation dosage. Gamma radiation is very penetrative, so the more material you have between you and the fireball, the better. Ideally, it would be something REALLY thick, like a mountain. Usually there's not a convenient mountain between you and the blast to duck behind,  but if you can get behind a landscape feature, or a large concrete structure (as long as it won't also fall and crush you) it will help. And anything is better than nothing!

The Next Few Hours: Threats include fires, structural damage, and the immediate fallout. About 20 minutes after the detonation of the Hiroshima atomic bomb, the burning of the large number of wooden structures combined into a firestorm. In the case of Nagasaki, however, there was insufficient fuel for the firestorm to form. The thermal energy of the blast can also vaporize a lot of water from the surface, which can condense on the fallout particles and drop back to the ground as "black rain."  It is extremely radioactive, so if possible, avoid exposure to it, and absolutely do not drink it. Unfortunately, many of the burn and radiation victims after the atomic bombing of Hiroshima were desperate for anything to drink, and so consumed the deadly black rain.

The Next Few Days to Weeks:  Now you're trying to limit your exposure to the longer-lived radioactive contaminants, like iodine, and minimize their damage to you. If you have them, take iodide tablets according to the instructions. This is especially important for children. It will saturate the thyroid gland with non-radioactive iodine and limit the absorption of any radioactive iodine from the environment. Taking vitamin C may also help your body deal with the damage of radiation exposure. Try not to inhale, eat, or drink any fallout. Food in sealed containers will remain safe even if exposed to radiation. If you have a shelter, stay in it. If you don't, you have to decide if it's better to try to flee the fallout area, or stay under whatever improvised cover you have. If you do have to go out, wear a dust mask, or make an improvised face cover. Before you go back into a shelter area, strip off contaminated outer clothes and leave them outside. Clean the fallout off your skin, but make sure not to embed it into your skin by over-scrubbing.

Finally, any event that results in you needing this information will also mean that the world has changed. At least a lot, possibly catastrophically. But try to help others if you can, and focus on staying safe, healthy, and alive.