EMP blast radius

With all the talk about terrorist attacks and most of the shows on the History channel, specially the last 2 months or so, it seems like thier warning us something is about to happen did any one see the show on about D.C. gettting nuked thats week?

You know the one if you watched it were all they wanted to do is protector congress and the shadow goverment and president after the attack the C.O.G. Continuity of government plan.

When anyways does anybody know blast radius and EMP distance if any one does can you compair a small medium TSAR bomb.

I hope this doesn't happen to anyones country its just wrong to use these bombs, our country had no right to us these bombs those people were innocent.

I have seen on the space-weapons episode of The Universe that a 1-MegaTon nuclear bomb, if exploded in space above Kansas, would create an EMP big enough to destroy electronics in the entire continental US.

Also here Is a picture that has a neat little map.

I heard that there was a nuke that could take out each major city simultaneously but with stuff like that emp we'd be so screwed it wouldn't matter.

You'd have to detonate a large weapon high in the atmosphere to have an EMP so great that it would knock out the whole of continental USA in one fell swoop. But, from my limited understanding, the same effect could be produced by only one small nuclear weapon. Because the problem is that if one small part of the electricity grid collapses it then has a cascade effect on the rest of the grid.

Some overgrown trees, touching sagging electricity wires during a heatwave in 2003, led to over 55 million people in North East USA and Canada losing their electricity supply. Strangely, the loss of electricity supply affected the electricity generating companies the worst of all, power stations went offline, computers failed ... and that just made the problem even worse, with the power failures cascading over a vast area.

Those structural problems still exist in the electricity industry, it's as vulnerable to cascading trips as it was 6 years ago, mainly due to a lack of investment. Heaven alone knows what an EMP event would produce, wouldn't be enjoyable that's for sure.