FORECAST FALL©OUT PLOT flue of folleout estimated to occur 2 hours and 10 minutes aftor Hehoure "he first cerca shown in the illustration around the maximum fall-out point is ~ nprroximately 250 square miles and the line inclosing this mroa indicates 6 rocntgen integrated infinity doso. smiles, and 3 rocntgens, otee The next aren is of approximatcly 759 square This example represents the prediction that may have been made for UPSHOT/KNOTHOLE, Second Shot on 24 March 1953. It is surprising how closely tho actual fall-out approximated the above predictione The maximum frileout at Lincoln Mince (48 miles from ground zoro) occurrcd at H¥2 hours and had ‘“s value of from 4 to 5 roontgen infinity dosc.e Ground rendings at Synnyside to Adaven (North to NortheBast of Lincoln Mineo) further verifiod the forccast plote tho tclemetering station approximately 15 miles north of ground zero verificd the ulose in falleout.e. This mcthod of snalysis must be used with cautione I[t should be remembered that this procedure applies only to 300 ft.s tower shots at NIG and when the cloud top reaches 36,000 to 45,000 fte msl (10 to 50 KT bombs). If the tower heights are lowered to 200 or 100 fte, of if the bombs aredetonated on the surface the contamination will increase by sovernl ordcrs of magnitude. If the ceguivalent bomb yield is significuntly less than 14 KT thon the cloud may only rvse to 15,000 to 20,000 fte msle Under such an evontuality the maximum fall-out will occur much closer to ground zero (within o radius of 20 to 40 miles), and the time of falleout will be more nearly one hour after Hehoure . @e th yn , buhes Sara Ne Me LULCJION Major, USF es a oy Control Officer Caamepenren*