There's an interesting article on Io9 about surviving a low-yield nuclear attack on your city. "Low-yield" here means in the 0.1 - 10 kiloton range that a terrorist might improvise, rather than the megatons a serious government could muster.

The timeline seems to be, first a bright flash. A shockwave follows some seconds later, because it travels more slowly than light. It can shatter windows, so don't go look out of one when you see the flash. Then there's some minutes of intense radiation. This fades quickly, and after about half an hour it can be worth moving out to seek a building that provides better shelter, if you know of one. At this point you're avoiding fallout. The worst of the fallout will have a relatively short half-life, and after 24 hours will should be safe to go outside for evacuation. Ideally, wait for emergency responders who will have better knowledge of fallout patterns and safe evacuation routes.

There's more detail in the article and linked paper. Perhaps the key point is that such incidents are survivable, as long as you aren't too close to ground-zero.

Well it will be more than just a bright flash, it will be a thermal flash with intense heat. What you wear day to day (assuming there is absolutely no warning) could prove the difference between live and death. Polyesters, nylon and other synthetics may well ignite or melt into the skin. Wool clothing will help considerably. Many will be blinded etc. Many folks won't instinctively duck and cover for the blast wave front.

The blast wave will destroy quite an area of property much depending on the construction. An air burst will generally destroy more property than a ground burst. A ground burst will generally generate more fall out.

Protection from fall out is best shown here;

http://www.youtube.com/watch?v=m6U9T3R3EQg



Typically staying in the protection shelter is 10-14 days. An NBC suit and respirator could prove very useful and can be had for less than £100. A portable Geiger counter would be useful as well for measuring the intensity of the fall out and its decay rate over a period of time.

re: thermal flash... in 1971, I was stationed on the southern Japanese island of Kyushu, about 60 miles north of Nagasaki... I was introduced to a lady that was a student nurse in 1945, and on the day of the bomb, she said she was about 12 miles from Nagasaki... she had fine line scars on her arm and shoulder... the pattern of dark embroidery on the white cloth of her kimono had absorbed enough energy to burn her arm in that pattern

And based on another recent thread we're all wearing fleece! Where do our preparations end...

Some of us are wearing wool beneath the fleece Will skin be protected from the melting polyester fleece by a thin layer of Merino Wool?

If you are wearing DragonFleece (Nomex) you don't have that problem.

Respectfully,

Jerry

Brangdon,

"Low-yield" here means in the 0.1 - 10 kiloton range that a terrorist might improvise, rather than the megatons a serious government could muster.

Really makes little difference, except on the distance from each required to avoid the initial heat and the time available to hide (longer from the larger blast).

AFLM,

The thermal flash from a ground blast (see original post) of low yield, will not provide a thermal blast that is a problem for very far. Buildings, terrain, trees,etc. will block the thermal effects at distances much beyond the serious damage zone. An air burst would provide a different problem.

Respetfully,

Jerry

I have some Massif(.com) nomex fleece but it's not for everyday wear. I also have more than a couple nomex flight suits which would be really nice to wear, but again, they're not an everyday thing. Terr's will need to give us a heads up when this thing is going down... yeeeah, that's not gonna happen.

Since there tends to be a fair amount of incorrect info regarding all things radioactive and nuclear on this forum, I thought I would post some more accurate info regarding the current topic.

Damage Zones for the Yields being discussed:
Damage Zones

Hypothetical Fallout Zone (which is of course dependent upon environmental factors at the time of the event):
Fallout Zone

I hope this gives people some accurate info to base their sheltering in place or evac planning on.

From the graphic we can see that the severe blast radius is approx 50% @ 1Kt to the 10Kt Radius. i.e. Yield to blast radius it is not linear.

Hiroshima was 16 Kt, which killed 90,000–166,000 people.
Nagasaki was 21 Kt, which killed 60,000–80,000 people.

I also have it from a good source that almost as many died from the fall out effects.

A low yield 1 Kt explosion would typically kill around 20,000-30,000 (blast and fall out) people in a high density population centre with many suffering severe burns.

AFLM,

You said "A low yield 1 Kt explosion would typically kill around 20,000-30,000 (blast and fall out) people in a high density population centre with many suffering severe burns."

I would expect this to be an exeptionally large number and I cannot be support it with the data you have presented. Even using the numbers from Japan, which are way too high for an American city, it would be hard to justify 20 to 30,000 deaths. Using the major damage radius of .5 miles for a 10 kt blast we find .79 square miles of major damage. For the 1 kt blast a radius of about .2 miles is .13 square miles of damage. Expect 4 times the area, so this is on the high end of Hiroshima (a 16 kt blast) using the 10kt number and way too high for Nagasaki (a 21 kt blast).

These are also for air blasts over tightly packed areas of poorly constructed (for protection from air blast) structures. Many (some estimates suggest 50%) of the deaths in these areas were from fire (see the effects of the firebombing on the Japanese cities. The nearest survivor was in a concrete building only 560 feet away (total about 2000 feet from 16 kt). For a ground blast in a major US or UK city like New York the effects would be far less.

Fallout deaths would depend largely on the sheltering, rescue and evacuation efforts taken after the blast. The fallout deaths in Japan were largly caused by a total lack of understanding of the problem by the residents and the government.

Respectfully,

Jerry

A nuclear weapon used by terrorists is almost certainly going to be either a ground burst, or very close to the ground.

It seems unlikely that terrorist groups will have the technology to make an effective rocket or missile that is both reliable and able to escape modern air defences.

A relatively crude home made weapon is unlikely to be light enough for hand delivery, so that suggests delivery by car or truck.
A less likely tactic would be detonation near the top of a large building, perhaps under the guise of delivering something heavy via a freight elevator.

There would be virtualy no hope for those very close to the blast, but as others post, survival at relatively modest distances is possible.

The distance at which survival would be likely would depend greatly on local factors. Presuming a regular grid layout of streets, then if the blast can be directly viewed, within say a mile, then the risk is likely to be severe.
On the other hand, a blast only a few hundred feet away might be survivable if several substantial buildings intervened snd thereby sheltered one.
The heat flash can kill, but an intervening building (even if it shortly afterwards burns down) has considerable sheltering effect.
The prompt radiation can kill, but an intervening substantial building gives a lot of protection (even if is is subsequently destroyed by the blast)

Fall out takes some minutes to some hours to become dangerous.

My action would be to run away from the blast if out in the open, and to shelter in place if already indoors.

Even the not very fit should be able to move a mile in 15 minutes, and a mile is a usefull distance when considering the relatively local effects of a small nuclear weapon.

If you realise what has happened before everyone else, you might be able to get a taxi or a bus, before everyone else has the same idea.

Unless you EDC a Geiger counter, a small nuclear explosion might initialy resemble a very large conventional explosion, such as might be caused by a large truck bomb.
If in the open, getting someplace else should be the first prioity.

There was an episode on this in 'Surviving Disaster'.
The link to the series doesn't work from the UK.
So here's the wikipedia entry:

http://en.wikipedia.org/wiki/Surviving_Disaster_(TV_series)

qjs

I thought this was the most interesting point to me. Instead of avoiding fallout at all costs, exposing yourself to it could be worth it if you can get to safer shelter in a reasonable time to ride out the rest of the fallout event.

A very large explosion has occurred in China.
There is NO SUGGESTION WHATSOEVER that this is a nuclear explosion, it is believed to be an accident involving dangerous goods.

The scale of destruction has however been compared to that expected from a low yield nuke.

A study of these pictures certainly suggests little hope for those very close to the blast, but a reasonable chance of survival a mile away.

Chinese disaster, pictures

I must again stress that this is a conventional explosion, but of a size arguably comparable to a low yield nuclear weapon as might be used by terrorists.
Interesting though tragic viewing.

My thoughts and prayers with the people of Tianjin.

This seems like it could be a case study of what happens when emergency responders and healthcare facilities are completely saturated. Let's hope that there's a way for us to get some lessons learned out of this.

Early indications suggest improper firefighting techniques may have been a major causative or contributing factor, specifically, application of water to fight fire in the presence of calcium carbide, which reacts with water to produce acetylene, the explosion of which may have then triggered a secondary, larger, detonation of nearby ammonium nitrate.

Spraying water around unidentified-chemical storage areas is often a Very Bad Thing. When these disasters occur, sometimes the chemicals were stored, handled or (un)labeled illegally or improperly, regulation or enforcement was inadequate or absent, or firefighter/first responder training, leadership, SOPs, or fire pre-planning and risk assessment were inferior, or, more commonly, there was some combination of these factors at work.

Ports and harbors are unique points for both concentration and risk exposure of vast quantities of hazardous materials, including toxic, highly flammable and explosive material with multiple potential combinations and reactions. Ports and harbors are also often adjacent to population centers.

See, e.g., the Texas City explosion that was America's deadliest industrial accident; the Phoenix City explosion; the West Loch explosion; and the Halifax explosion in 1917 that killed 2000 people.

My fear for the delivery of an actual terrorist nuclear device would be in a standard shipping container aboard a cargo vessel, perhaps combined with a takeover of the cargo vessel itself in order to force it in as close as possible to, e.g., the civilian population ashore, a large cruise ship with many thousands aboard, or vulnerable fuel or chemical tanks, etc. It is extremely hard to stop a large cargo vessel and neither the military nor the USCG are likely to have the means immediately at hand to do so.

A far simpler but probably far more likely "dirty bomb"used to spread radioactive debris with a conventional explosion could be easily employed as you suggest, and many other means, as well.

Basic radiation detectors are becoming more affordable, easier to use, and more widespread. They are increasingly common in places like ERs and on fire apparatus. One time use detectors are very cheap, a simple continuous keychain-sized radiation detector like the "NukAlert" is available for under 150 bucks, and more sensitive sophisticated monitors are under 1,000 dollars.

It's true that radiation detectors are much more easily available to the general public than ever before. Apart from conventional Geiger counters there are solid-state alternatives that rely on photodiodes or CCD cameras. You could even get an app that transforms your smartphone into an improvised radiation detector. Not nearly as sensitive as a Geiger-Müller tube but sufficient for dangerous levels of Gamma radiation at least.

Also, it is easy to make your own Geiger counter if you have some basic electronics skills. I've played a lot with ex-Eastern Bloc Geiger tubes that are all over eBay. You can get one for $20 and they work very well. If anyone needs good schematics I'd be happy to help.

The only tricky part is the high-voltage power supply. This one is really good:
http://www.techlib.com/science/geiger.html

As far as power consumption (under 1mA if you know what you're doing) it is actually far superior to most commercial devices. A single 9V block battery or a couple of AA(A) cells will last a long time. The circuit can be calibrated to give a pretty accurate reading.

If you are interested in this topic and happen to be involved in the medical part of disaster response, I highly recommend taking the Advanced Radiology Life Support Course. It's usually quite expensive as a freestanding course, but sometimes you can catch one offered as a conference pre-course at much lower cost, and the training is focused and excellent.

Also, if you are any sort of medical, LEO, Fire/rescue or other emergency responder, you are probably eligible to attend the National Center for Domestic Preparedness. They offer several different radiological/CBRNE related courses, and all expenses are always free of charge, including housing and meals. https://cdp.dhs.gov/

Some good comments above.
But a couple of misconceptions need to be cleared up.

The explosion of a nuclear bomb happens SO FAST - there is no reaction time. You cannot duck. You cannot say "What's that?". It is game over. If you are unlucky enough to be near the site of the blast, you will get the effects.

The principal effect is HEAT - terrible heat. If you look at the accounts of the scientists who witnessed the Trinity Test - first A-bomb test. They were about 10-miles from the test, and wearing protective glasses. They remarked that the heat, from that distance, was so intense that it felt like someone had opened the door to a very hot furnace. It was so strong, you almost couldn't handle it. That was from a distance of 10-miles.

There is an ONLINE site somewhere that shows eyewitness accounts from Hiroshima and Nagasaki, immediately after those weapons were dropped. You see images (sketches) with many people with terrible burns. Whatever part of your body is exposed, severe burns. The rivers were full of bodies from people who ran to the water because "their bodies were on fire" ... and they died floating in the water.

I wish I could find the ONLINE Web site. Maybe somewhere here can post it.

You can't "shelter" from the nuke. You just pray that you are lucky enough to be far away from it.

Pete

If you have a look around you at the moment you probably won't be able to see much of the sky so a surprise detonation probably won't affect you, also cloudy/hazy skies attenuate the propagated flash energy considerably.

The blast wave moves at the speed of soundish so a blast 10 miles away would take some 45 seconds to arrive, quite a lot of time from seeing the flash to take some shelter from the ground wave or get out a vehicle and get into the curb to avoid translation.

It is not all doom and destruction.

During transition to war we used to wear one eyepatch so if we did get caught by the flash only one eye would be damaged.

I agree. I also think that a lot will depend on multiple unknowable factors such as weapon design, yield and delivery method. Much of what's been learned and disseminated about nuclear weapons effects on civilian populations was predicated on Cold War hypothesizing involving high yield weapons, air bursts, etc.

But in the meantime, increasing accuracy in delivery systems has led to the development of lower yield nukes than were deemed necessary in the past. The newer members of the Nuke Club like India, Pakistan and Israel, as far as public estimates go, also don't appear to have built very high-yield weapons either, in part because their likeliest targets are rather close by, not on the other side of the planet.

Thankfully, international arms control and accountability programs, etc., seem to have reduced the risk of a state-built nuke, or materials and experts, getting into the wrong hands, although Pakistan's stability and internal security is worrisome. Still, the risk that a non-state terrorist group might acquire or even build one remains, and from their POV there's no better place to use a nuke than against the Great Satan.

But if that happens, I think it's reasonable to expect it to be a rather low yield, ground or low-altitude detonation, which would be a catastrophe to be sure, but not a city-killer inflicting many tens or hundreds of thousands of deaths. It's even more likely, I think, to be a simple dirty bomb or an at least partially failed detonation. So most people, including many of those rather close to the detonation, can or will survive, although the result may be almost as effective for the bad guys, since it would still be "nuclear" and thus carry much the same psychological impact and likely cause similar political and economic disruptions.

The other remaining risk is an accidental nuclear attack. There have been several very close calls that we know about between us and the Russians/Soviets where somebody almost got nuked. Many experts seem to think such an accident is far more likely than an intentional use. We were only saved before because cooler heads prevailed, and, hopefully, any such future accident will not result in major nuclear exchanges.

https://www.youtube.com/watch?v=NZAHpuY_sCo

No one wears eye patches nowadays. The computer guidance systems don't need em!

This was the Royal Observer Corps. We had to go out of shelter during TTW and after Attack Warning Red to get data for weather forecasts and after a nuclear attack to retrieve instruments and have a good look around. The problem was a second explosion whilst this was going on. Still got the patch.

The last flying Vulcan's last flight is soon, 26th September. The end of an era.

Vulcan appearances

I once spoke to a retired USAF officer a few years ago and showed him a recent Vulcan display video. He didn't recognize the airplane, he thought it was a new prototype...

To think my Aunt in the RAF used to directly work for MacMillan. He was absolutely terrified during the Cuban Missile crisis and he did suffer the Nightmares all those years ago

https://www.youtube.com/watch?v=4QP02Jf1Vl8

"The problem was a second explosion whilst this was going on. "

THAT would be the "understatement of the day" on this thread!!
Hahahahaha! Glad that you are still with us.

The Vulcan was a DARN cool looking piece of machinery!!
Great choice for James Bond on Thunderball :-)

A Vulcan performing a half Cuban 8...Don't try this with a B52, B1b or B2..

https://www.youtube.com/watch?v=yG_wAdMBMB4