Se Lacie of fall-out informstion from previous shots of couparabis. yield ves5 serious handicape Be The yielé ef MATO wae three tine the moet probehlevales anétulee the probable upper limit «ith the result that more debrie wae carries up and diffused over a anch larger aree than wethought possible. ¢, The original scares carmet be considered <8 © pain’ or a relatively emall ares tut mist be ecnsidered te be a area of about fifty miles in dianster, This dlenster alse depends on yield. ad. The radiocactiuity ef the debris can be considered prepertiaal to yield, Radicactive aaterial in the BRAVO cloud wee thus two te three. tinea than was expected. Ce NeateLe rretetcn Of she cnoerved fallnow eas cooly ve ageounted for by essuming thas i originated in the stratosphere. For such particles to reach the ground at observed times, their dtanster mat have been in exsese cf 100 nisrens, 4 f. Foresast for shot time vinds at shot tine we essentially correct. Variation from forecast trajectories we approximately 10 degrees in significant u ieat.unfortunately, the variatios was in tite wrong direction (See Incl & The small variations observed at lower levels were also in an unfavorable direction. Nevorthelesa, the aescuracy of the winds aloft forecast approached the limits of accuracy of the ywind observations themselves ond wore well within the normal forecast Orrer, ‘ge Tue fallout pattern extended from the BIKINI Atoll te the east northeast, Considerable widening of the pattern tock ‘@iffueion. The intensity of the pattern on theground wes due primarily to superposition of mehrocm cloud fall-out on the and the superposition can be attributed to the narrow came within which the winds were acting, The theory thet a significant fall-out dees not coma from tha stratosphere is not substantiated by the facts of FRATO. he For future high yield shots, the forecast and observed winds for the first twenty-four hour post~shot period should receive ase mch emphasis as analyses made for shot tine, K-18