How to Survive the First Hour of a Nuclear Attack

This article originally appeared on Tonic.

Nuclear bombs have been on people's minds lately as tensions with North Korea escalate. For government agencies and disaster planners, however, nuclear bombing is on their minds pretty much all the time, regardless of the news cycle. But the typical scenario the government looks at has less to do with long-range missiles and Cold War-style total annihilation, and more to do with ground detonation of a nuclear bomb set off by terrorists—specifically, a 10-kiloton (KT) nuclear bomb. For perspective, a 10 KT bomb is a little smaller than the size of the bomb the US government set off over Hiroshima, and is equivalent in strength to around 5,000 Oklahoma City truck bombs. (North Korea's nuclear bombs are thought to be around that same size range as well.)

Chances are even if you're ultra-tuned in to the latest terrorism threats, you haven't encountered much of the preparedness literature that the federal government has produced on Ready.gov. Government agencies are always refining the safety responses to nuclear threats—coordinating agency responsibilities, and even running models of what a nuclear detonation would look like in large cities such as LA and Washington DC. Just recently, a government grant was awarded for a computational modeling project at George Mason University looking at how individual people would react in the first 30 days following a nuclear attack on New York City.

So let's say one of the worst-case scenarios from one of those government models did happen, and somehow a 10 KT nuclear bomb was detonated without the US having advance warning. Here's a timeline of how that nightmare would likely play out in a major city like New York or Washington DC—and your odds of making it out alive.

The First 15 Seconds
If you're still alive, you're probably at least a mile from where the bomb went off: A 10 KT nuke won't level an entire city, but it will cause significant damage, especially near the blast site. That means somewhere around 75,000 to 100,000 people are likely already dead—they were the poor souls who were in a half-mile to one-mile radius of the bomb site, says Irwin Redlener, director of the National Center for Disaster Preparedness at Columbia University. Most of the buildings there are gone, too, says Brooke Buddemeier, a certified health physicist at Lawrence Livermore National Laboratory. Even as far as a mile out, you're probably seeing significant damage. And between one and three miles out—the so-called "light damage" zone—glass shatters with enough force to injure people, Buddemeier says, as a fireball as hot as the sun shot up to five miles into the atmosphere, pulling dirt and debris with it from the collapsing buildings.

Minutes 1 to 15
Mayday. You've got ten to 15 minutes to seek shelter. Buddemeier can't emphasize this enough: You don't want to be wandering outside when all that dirt and debris, now broken into radioactive particles the size of sand and salt grains, falls back down to the ground, causing radiation poisoning in those exposed to it.

Radiation poisoning is no joke. Look no further than Brazil in 1987, when the radiotherapy source of a teletherapy machine was stolen from an abandoned hospital by two men who thought it might have scrap metal value. They took it home and dismantled it further, exposing themselves to more radiation before selling it to a scrap yard, which sold it to another scrap yard, whose owner in turn brought the radiotherapy source into his house. The end result was four deaths, 249 people receiving significant radiation exposure, and the Brazilian government leveling several houses for safety. And that's just from the glowing insides of a teletherapy machine. In addition to causing death from high exposure in a short time, radiation poisoning can also cause blistering of the skin and severe damage to bone marrow, the lining of the lungs, and the gastrointestinal tract, as well as long term side-effects like leukemia.

So now panic ensues. You're one of the lucky ones, far enough from the blast that you weren't hit by collapsing debris or a nasty flying shard of glass. Forget the Toyota, Buddemeier says—gamma radiation will come right through the glass of a windshield or through the thin metal of modern cars. The more layers of concrete and brick you can get between yourself and the nuclear fallout, the better. It'll accumulate on roofs, so stay away from the top floors of buildings. New York City's most in-demand real estate is also the most protective, as it turns out: A nice thick-walled, prewar apartment building or a brownstone works great. The center of an office building, a cement underground parking garage, or deep in the bowels of the subway system in a city like New York will also offer excellent protection.

Minutes 15 to 60
You're all set to run into a nearby office building, but at the last second, you spot a couple of lost, scared children. Radiation be damned, you're going to help them. Good for you, Luke Cage—only now, those sand-sized particles are falling back to Earth, getting in your hair, on your coat, your shoes as you hoof it towards the nearest brownstone. Now you're at risk of radiation poisoning. The extent of the damage is going to depend on how close you were to the bomb site and how soon after the blast you got exposed. When it comes to radiation after a nuke, "what we are really worried about is those acute effects," Buddemeier says, that happen when a person is exposed to high doses of radiation in a short amount of time, enough to make someone vomit. The gastrointestinal tract is sensitive to radiation, so if you start puking very soon after, it's a sign that you've absorbed a significant (read: potentially deadly) dose.

Obviously, you need medical care. As a first defense, a medication called Prussian blue can be administered orally to help the radiation pass more quickly through the body, Redlener says, but you don't even know where to begin to find that. Most people don't: Our supply of that medication is "pitifully inadequate" for a nuclear bomb scenario and there is no system to distribute it, he says. The only course of action you have, then, is to get into a shelter and try to minimize the damage from fallout by removing the particles from your body—that'll at least shorten the duration of your exposure a little. First things first: Remove your clothes and brush the particles from your hair. The shower's probably busted, but if you can locate water, get to work washing yourself off—and be gentle. Scrubbing too hard could leave scratches and push those radioactive particles into your skin.