NUCLEAR FEARS: How to increase your chances of surviving an atomic blast (The Economist, January 20th, 2018)
“THE alerts mistakenly sent to residents of Hawaii, warning them that a missile was on the way, were a reminder of an era when terror was measured in kilotons. In the 1950s and 1960s public-service broadcasts informed Americans about what to do in case of a nuclear attack. Since then, with nuclear conflict seeming less likely, such knowledge has seemed esoteric, like taking an interest in Brutalism or taxidermy. Here is a reminder of something we hope you will never need to know.
If a nuclear bomb exploded in an airburst, around 90% of people would die instantly near the centre of the blast: a roughly 1.9km (1.2-mile) radius for a 300-kiloton (KT) device—the estimated force of the weapon North Korea tested in September. Within a 15-square-kilometre area, at least half the population would die more slowly, from radiation and burns. Those who make it through the blast or are farther away can take steps to increase their chance of survival.
An explosion would generate a fireball of light many times brighter than the sun. Do not look at it or you may go partially blind. Instead, do as the cold-war safety film featuring Bert the Turtle advised: duck and cover. Lie down, ideally underneath something. This is to prevent serious burns from a thermal pulse, or heatwave, lasting several seconds that will sear through the area, setting off fires. It is also to avoid shattered glass and flying debris as a blast wave, with hurricane-strength winds, follows. The energy from the fireball would draw a column of dust and debris three miles into the atmosphere for over ten minutes; its top will flatten into the cap of the mushroom cloud.
During that time, blast survivors need to find shelter. Radioactive fallout—highly contaminated debris that settles on surfaces—follows. It is most lethal just after the blast. The ideal shelter is below ground and well-sealed. If you are in a building above ground, go to its centre, preferably avoiding the ground or top floors. With luck your shelter has bottled water and non-perishable food; a radio and batteries for emergency information; wet-wipes and plastic bags for personal sanitation; and your identification documents.
Assume mobile phones do not work. Distance from the blast is a matter of luck. Surviving thereafter is mostly a matter of finding shelter, says Alex Wellerstein of the Stevens Institute of Technology in New Jersey. After about two days the worst of the radiation will have decayed. It may be safe to go outside.
The best step, though, is not to have a nuclear missile come your way at all. Which is why some in the Trump administration argue for a strike on North Korea soon; and why most other people think that would be insane.”