"Duck & Cover!" It actually wasn't bad advice despite all the mocking it gets.

[EX500rider]

Yes if you are within a mile or 2 of ground zero it would not help, but the further away you get, in the 5 to 10 mile range it could be life saving. 1st to save you from flash burns and then to to save you from flying glass.

More people will be outside the total destruction zone then in it, at 8 to 14 miles from a one megaton explosion flying glass and flash burns will be the biggest danger, at 14 miles the shockwave will already have dropped to 1 psi, .5psi at 21 miles. And most modern nukes are more in the 200kt range due to size and weight restrictions in the nosecone.

"But I'd rather die right away!" you say... Unfortunately at ranges over 5 miles you aren't going to unless you are unlucky/lucky, but you will get terrible burns and terrible glass shards imbedded in you, I don't think that's the way you want to go, you can always pick a easier less painful way out later.

A 1 megaton explosion will have a 200psi shockwave at .5 miles but that drops to 15psi at 2.2 miles and 5psi @ 5.5miles (which is still enough to collapse wood frame houses)

All figures taken from my copy of "Life After Doomsday-Survivalists Guide to Nuclear War" Paladin Press; 1st Edition (January 1, 1980) Still some used copies on Amazon.

[Hassin Bin Sober]

1. I read that a website showing blast radius scenarios recently crashed from too much traffic.

I read that while searching for websites showing blast radius scenarios.

[IrishAfricanAmerican]

2. My elementary school...

was about 500 yards from the runways on a USAF SAC base. That we would all be vapor was never in doubt.

[BlackSkimmer]

3. That must have been a loud school.

I lived on a SAC base, and my barracks were pretty noisy sometimes, but we weren’t in an educational type situation.

[IrishAfricanAmerican]

4. When they were running ops...

it was indeed very loud. The Vietnam war, (carpet bombing,) was going on so, yes, a lot of activity.

[EX500rider]

5. yeah that close you will be ashes in seconds but the further you go the better that advice is nt

[ProfessorGAC]

6. Partially Agree

I agree in would help avoid debris injuries.
However, in those old promos, they specifically stated "If you see the flash...".
Too late to avoid flash burns at that point.
If a plan was to get below windows as a detonation was imminent, than they'd be onto something.

[EX500rider]

7. Strangely enough it depends on the size of the weapon with smaller being worse/faster

A 20kt device releases it's thermal pulse in a 1/3 of a second. A megaton weapon on the other hand releases it's thermal pulse in a period of 5 to 20 seconds. Also depends on the weather as a bomb detonated above the cloud layer will have much reduced thermal flash due to reflection/scattering effects while one that goes off under the clouds will have increased effect.

(from Table 4.1 in the above mentioned book...which I hoped I'd never have to dust off...or check the batteries in my CD Geiger Counter)

[ProfessorGAC]

8. How Close Are We?

I read that as the length of time the light pulse last. Because of the "slow" reaction rate of the fusion chain, the conditions for that nuclear reaction last longer. Hence a longer period of light.
The flash burns are caused by uV, XRay, and intensity of visible light.
The power of the weapon has nothing to do with the speed of light. So, at 10 miles the light still gets there in a bit more than a half millisecond.
I grant that if folks ducked after the flash they might miss 10 seconds of hot light. Possibly good.
But, if fission bombs caused flash burns in 1/3rd of a second, so would the light from a fusion bomb. It's just that said light might last 50 times longer.
Better to be slightly burned that badly burned, I suppose.