z Sy INTRODUCTION The detonation of the most powerful explosive device produced by -man ~ a thermonuclear bomb - rightly concerns many as to the effects produced on the earth and its atmosphere. Detonation of atomic devices has led to conjecture that all manner of weather phenomena have resuited droughts, -floods, tornadoes and typhoons. Operation CASTLE offered an opportunity to observe qualitatively, at least, some of the effects, if EEU100S any, of high yield explosions upon the weather. ii