I was half asleep late the other night, watching the history channel, when they showed some old footage of an atomic bomb test. It is one of those stock footages that we have all seen maybe a hundred times. But something caught my eve this time. To one side of the mushroom cloud were several columns of smoke clearly visible, going almost straight up, looking as high as the mushroom cloud itself. What were they? I would think that the force of the blast would push any smoke ahead or away of it until it settled, but it seems that these smoke columns formed simultaneously. Any ideas?
I think those were the trails of smoke from rockets that were fired as a check on wind direction and on the degree and timing of mixing of the debris from the blast into the atmosphere.
Davis Simmons is right - see http://nuketesting.enviroweb.org/hew/Usa/Tests/SmokeTrails.html