Mushroom clouds

[JRNC26]

I know weather and terrain play a major factor in this question.But,does anybody know how far away a mushroom cloud can be seen?

[madcritter]

here is a little old history for an idea on it.

"The energy released by the bomb was powerful enough to burn through clothing. he Tokyo control operator of the Japanese Broadcasting Corporation noticed that the Hiroshima station had gone off the air. He tried to re-establish his program by using another telephone line, but it too had failed. About twenty minutes later the Tokyo railroad telegraph center realized that the main line telegraph had stopped working just north of Hiroshima. From some small railway stops within 16 kilometers (10 mi) of the city came unofficial and confused reports of a terrible explosion in Hiroshima. All these reports were transmitted to the headquarters of the Japanese General Staff. Military bases repeatedly tried to call the Army Control Station in Hiroshima. The complete silence from that city puzzled the men at headquarters; they knew that no large enemy raid had occurred and that no sizable store of explosives was in Hiroshima at that time. A young officer of the Japanese General Staff was instructed to fly immediately to Hiroshima, to land, survey the damage, and return to Tokyo with reliable information for the staff. It was generally felt at headquarters that nothing serious had taken place and that it was all a rumor. The staff officer went to the airport and took off for the southwest. After flying for about three hours, while still nearly 100 miles (160 km) from Hiroshima, he and his pilot saw a great cloud of smoke from the bomb. In the bright afternoon, the remains of Hiroshima were burning. Their plane soon reached the city, around which they circled in disbelief. A great scar on the land still burning and covered by a heavy cloud of smoke was all that was left. They landed south of the city, and the staff officer, after reporting to Tokyo, immediately began to organize relief measures. Tokyo's first knowledge of what had really caused the disaster came from the White House public announcement in Washington, D.C., sixteen hours after the nuclear attack on Hiroshima. By August 8, 1945, newspapers in the US were reporting that broadcasts from Radio Tokyo had described the destruction observed in Hiroshima. "

[Denny367]

If you are close enough to see it, you're too close!

[southernman82]

Back to your original question of how far the cloud is visible for. Denny367 does have a good point that if you can see it you're too close for comfort. However, if the winds are blowing west to east and you're west of the cloud it's best to move further west.

The size of the cloud is dependent upon the size of the nuke. Find that out and you should be able to determine how far you can see it for. There are some open source software out there that you can grab to plot the theoretical impacted area.

Also, keep in mind that an actual nuke going off within our borders is highly unlikely. I would be more concerned about a "dirty bomb" going off in a metropolitan area or one of the major fresh water resevoirs.

For those that are unfamiliar with a dirty bomb it is a traditional explosive device that is laced/intertwinned with radiological material. The conventional explosives disperse the material. Most of the readily available radionuclieds are easily removed through decontamination. The issue with these types would be the risk of inhalation.

[Robot]

How far away can naturally occuring large objects be seen? Conventional explosions, if large enough, can make a mushroom cloud. Altitude, relative humidity, etc. are all variables in your question.

When I use to fly in Colorado, on low humidity days, I could see Pikes Peak from over 100 miles away. Most likely I could have spotted a large enough mushroom cloud.

[SMM123]

A small ground burst nuclear mushroom clouds reach 45,000' in height. On a clear day using line of sight calculations, you could see the top of it from up to 60± miles away. However, from that distance it would just look like a regular cloud top and/or blend in with the horizon.

If however, a huge 57MT type weapon was detonated (Tsar bomb), its mushroom cloud can easily reach heights of 210,000'. This could easily be seen from great distances, especially since it will be highly lit by the explosion.

How about this for some scary ****:
One of these on NYC would instantly incinerate 10 million people with ease.

http://www.youtube.com/watch?v=FfoQsZa8F1c