How to shelter from fallout after a nuclear attack on your city

Graph: Fallout: miles from ground zero vs. siz of bomb in kilotons


How to shelter from fallout after a nuclear attack on your cityExpand

Terrorists have detonated a low-yield nuclear warhead in your city. How long should you hide, and where, to avoid the worst effects of radioactive fallout? We talked to Lawrence Livermore National Laboratory atmospheric scientist Michael Dillon to find out.

Yesterday Dillon published a paper on this topic in the Proceedings of the Royal Society A. He’s spent his career researching how the government should respond to disasters with an airborne component, whether that’s a chemical accident, an epidemic, or nuclear fallout. After poring over dozens of studies on how fallout behaves, and analyzing as many factors as possible related to urban detonations, he’s come up with a disaster plan that he hopes can be implemented by governments from the local to the federal level.

The best part of Dillon’s fallout plan is that it’s aimed at people like you and I, who won’t have access to information about wind direction and blast magnitude. It’s a plan that works even if all you know is that a nuclear bomb has gone off in your city.

This Is Not A Cold War Bomb

When I spoke to Dillon about his work, he was quick to point out that his disaster plan is still theoretical. Nobody has yet had a chance to study a low-yield nuclear blast in a real-world city — “thankfully, these are rare events,” Dillon said. But as the threat of a terrorist nuclear attack grows more likely than a Cold War scenario, it’s crucial for cities to have plans in place. And that means a major paradigm shift in how we think about nuclear attack.

The classic nuclear attack scenario that most of us imagine comes straight out of the Cold War — or movies like Terminator. Multiple megaton-class bombs go off all over the world. The results are catastrophic, with whole regions burned to a crisp, mass deaths, and a fallout plume that stretches hundreds of miles. But the scenario we’re more likely to encounter today involves bombs that are anywhere from .1 kilotons to 10 kilotons. They’re small compared to the bombs that leveled Hiroshima and Nagasaki, and infinitesimal compared to the warheads we had in our Cold War arsenals.

“These events are more like a Katrina-level disaster,” Dillon said. “Your city has the potential to survive, and that’s what we’re planning for.”

The chart below gives you a sense of the damage radius of the bombs that Dillon studies, as opposed to Cold War weapons. The worst damage occurs in the pink areas (psi stands for pounds-force per square inch, and is used to measure blast force). People inside the pink dotted line run the risk of getting pretty severe burns, and those outside are more at risk for doses of radiation and injury from fire or other blast damage. What’s most important, though, is that you can see the range of radiation danger is much smaller with today’s nuclear bomb threats. A 1 kiloton warhead will pose a radiation danger up to 2 kilometers away from ground zero. Compare that to a 10 megaton, Cold War bomb, which irradiates areas as much as 40 kilometers away.

So you can appreciate why a nuclear attack today doesn’t have to mean instant death for everyone around — and could even be something that your city would recover from.

How to shelter from fallout after a nuclear attack on your cityExpand

Taken from the Student Guide to Federal Nuclear Detonation Response Planning

What To Do When the Bomb Goes Off

If the bomb goes off and you are unhurt in the initial blast, you need to worry about protection from radioactive fallout. Because we’re not in a Cold War world anymore, Dillon said, “You don’t need a specific fallout shelter to get the protection you need.” You just have to be aware of what kinds of buildings will provide adequate shelter and which won’t.

Emergency responders measure the effectiveness of a fallout shelter on the “PF” scale (you can see a FEMA guide about that here), but Dillon is assuming you won’t have PF numbers on all the buildings in your neighborhood. What you want to do is try to find what he calls “adequate shelter” in the first 30 minutes after the bomb goes off. What is adequate? Said Dillon:

Put as much mass and material weight between you and bomb as possible. Distance [from the blast] is good but weight — heavy things, concrete, large stacks of books, earth — those are good. Go underground, if you can get there. Again, you’re looking for concrete roofs and walls. Even just deep inside big buildings. A basement is the classic spot.

Think about your city. Where is the nearest adequate shelter to your home and your work? Is it a subway station? A library with thick concrete walls lined with books? Your basement? A large building with lots of interior rooms that are shielded by many walls? Dillon warns that you want to try to reach this place in 30 minutes, but don’t count on being able to drive there. Traffic may be at a standstill. Make plans that will allow you to walk or possibly bicycle to your adequate shelter.

How to shelter from fallout after a nuclear attack on your cityExpand

Then the question becomes how long to wait in this shelter until it’s safe to go outside. In the movies, of course, we see all kinds of ridiculous scenarios, from people going outside within minutes to whole civilizations remaining underground for centuries. None of those are really accurate, said Dillon.

Your best bet is to stay until emergency responders come. Given that we’re talking about a low-yield bomb, which may have a blast radius of less than a mile, this isn’t a disaster that has taken out the nation’s power structure. Help will arrive soon. But let’s say nobody does come. Dillon says his personal preference would be to wait about 12-24 hours before going outside. But, he emphasized, “wait for emergency responders because they’ll help with an evacuation route.” You don’t want to jump out of your fallout shelter and walk right into the path of the radiation.

How Does Fallout Work?

My first reaction to Dillon’s advice was disbelief. I could be relatively safe walking out of a fallout shelter less than a day after the blast? The answer is yes, because the most immediate danger is from what’s called early fallout, which is comprised of radioactive particles that are heavy enough to fall within hours of the blast. They usually fall in zones fairly close to the blast, depending on wind direction and intensity.

How to shelter from fallout after a nuclear attack on your cityExpand

Said Dillon, “It’s going to be falling for hours after the blast. These large particles are the most dangerous and have the highest levels of radiation. This is the stuff that’s going to make you physically sick immediately.” He contrasts the radiation sickness you can get from this early fallout to other kinds of illnesses, like cancer, that you can get many years after radiation exposure. Sheltering from fallout may not prevent cancer in the future, but it will prevent you from dying immediately of radiation exposure.

How to shelter from fallout after a nuclear attack on your cityExpand

The other thing to keep in mind is that fallout isn’t a magical substance that floats everywhere and gets into everything. “There will exist a physical region that’s contaminated with highly radioactive particles,” he said. “After leaving the shelter, you want to exit that region.” That’s where emergency responders can help, of course — they’ll be able to tell you how to avoid that zone, and how far away to go. Certainly there are lighter fallout particles that can stay airborne for much longer than the early fallout, but those particles are not going to cause immediate radiation sickness — which is what you’re trying to avoid in the bomb’s aftermath.

Dillon added that the early, dangerous fallout also “decays really fast.” The “dangerous zone shrinks quickly, and it’s a lot safer to be outside in 24 hours” than it is an hour after the blast.

How to shelter from fallout after a nuclear attack on your cityExpand

Our pop culture is still straining to catch up with a world where nuclear blasts result in a scenario more like Katrina than On the Beach. We’ve been trained to think of nuclear attack as the end of the world, but it’s like many other disasters: horrific, but something that we can survive. While we’re waiting for a movie that realistically depicts a low-yield nuclear attack in the post-Cold War era, we can start planning our real-life escape routes and shelters in the citiscapes around us. One day, that big ugly building downtown with the thick concrete walls could save your life.

Read the full scientific study in Proceedings of the Royal Society A

Unless otherwise specified, all charts taken from the US national security staff publication Planning Guidance for Response to a Nuclear Detonation

Waffling: How FEMA determines how bad a disaster is

Waffle House


When disaster strikes, swift and decisive actions are typically required. Waffling — as in equivocating – is probably not a good idea. But waffles, the food?  In the United States, they are a leading indicator as to how bad a disaster is.

Just ask Federal Emergency Management Agency (FEMA) head W. Craig Fugate.

On May 22, 2011, a multiple-vortex tornado with winds breaking 200 miles per hour hit the town of Joplin, Missouri. The city was ravaged, with over 150 people killed and nearly 1,000 injured. An estimated 10-25% of the city demolished, depending on which report one goes by. Roughly 2,000 commercial buildings were destroyed and another 7,500 houses were as well. In total, the insurance claims from the damage will pay out over $2 billion.

Fugate was well prepared to help assist in the recovery; he is well experienced when it comes to disasters. A former firefighter, Fugate ran Florida’s emergency response programs in the early part of this century, overseeing recovery from multiple hurricanes as well as floods, wildfires, tornadoes, and the like.  He was appointed to the head of FEMA by President Obama in 2009 — a position he had held since.  His decades of emergency management mean we should probably take his ideas seriously, even if they sound ridiculous on their face.  Which brings us back to waffles.

With such carnage hitting Joplin, it would take a miracle for any businesses to have figured out a way to remain open.  Or, if not a miracle, a detailed, proven disaster action plan — which is what the two Waffle Houses in the town had in place.  As discussed by safety publication EHS Today, these all-day breakfast restaurants have business plans in place which help them stay open.  A Waffle House affected by disaster can quickly determine which employees are able to make it in; have temporary food storage areas ready for action; and have secondary, limited menus available in such a situation.  And in Joplin, both of the Waffle Houses remained open for business.

Fugate observed that Waffle Houses were able to defy the will of nature. He used this curiosity to create a back-of-envelope disaster rating system, one which resonated colloquially, called the “Waffle House Index.”  A “green” rating means that the Waffle Houses are open, with full menus, minimal to no damage, and with working power.  A “yellow” rating means that the restaurant is serving a limited menu, indicating low food supplies and/or struggles with power (perhaps the establishment is using a backup generator).

And when the Waffle House is closed?  The Waffle House Index hits a “red” rating.  That’s rare, and, as Fugate noted in a speech (per Christian Science Monitor), “that’s really bad. That’s where you go to work.”

But don’t worry — even though the Waffle House Index in Joplin only hit yellow, FEMA and other emergency response teams were there anyway.

Bonus fact: Waffle Houses serve breakfast all day.  McDonalds does not — they stop serving breakfast foods at about 11 A.M., depending on individual franchises.  Why? Because the breakfast foods cook at a lower grill temperature than the regular burgers-and-sandwiches (but not hot dogs) menu; once the grill is turned up, breakfast can no longer be prepared.

Why Social Media Is the Front Line of Disaster Response

Social media statistics in disasters

An infographic from Hurricane Sandy, but equally relevant in the aftermath of the Oklahoma tornado yesterday.

By Zoe Fox from

Nearly one million people are affected by natural disasters each year. In the U.S. alone, some 400 people die from disasters that cost the economy $17.6 billion. Helping respond to these cataclysmic events, social media is now a go-to tool for those effected by disasters.

One in five Americans has used an emergency app. Of those Americans effected by natural disasters, 76% used social media to contact friends and family; 37% of used social media to help find shelter and supplies; and 24% used social media to let loved ones know they’re safe.

SEE ALSO: 13 Gadgets to Prepare You for a Natural Disaster

This infographic, created by our friends at USF’s Online MPA, details how social media has revolutionized communications during natural disasters.

At the bottom of the infographic, you’ll find a FEMA tweet sent during Hurrcane Sandy, which exemplifies why social media is becoming the best way to spread information during dangerous events: Phone lines can get congested, so updating social networks can be the ideal way to let loved ones know you’re okay.

Homepage image courtesy of iStockphoto, Krakozawr