we oNo . 1 March 1954 MEVOZANDUK FOR RECORD: SUBJECT: | Command Briefing, 0000, 1 March 1954 Members present: Gen. P.W. Clarkson, Gen. &. tcGinley, sen. He Estes, Dr. A.C. Graves, Dr. W. Ogle, br. J. Reeves, Dr. De Sewell , Capt. W.L. Knickervocker, Col. W.S. Cowart, Capt. R. a. Maynerd, Lt Col c.D. Bonnot, Lt Col R.&. House. 1. In generel, the forecast presented at the midnight briefing was confirmed, except that in the levels between 5 end 15 thousend feet toe forecast was light and variable. In an atterpt to delineate direction to these winds, it was determined that the best forecest that could be given was for +ue 10 thousand foot level. This was forecest to be westerly &t 10 knots as the most pessismistic situation. Consequently, the hodosraph plot vas made using the 10 thousend foot westerly wind in order to present the most pessimistic situation which would occur. This picture gave resultant winds in the direction of Rongelap end Rongerik, -however, it was considered thet the Cistence to Ronselap and Rengerik cocpered to the resultant wind speeds were such that no fell-out should reach those atolls. From the forecast hodogreph the tims of travel to Rongelap wceuld peve dean ebout 12 to 15 hours. The hodograph plot did however show that certeinly TARE site would be heavily conterinated, a most likely NAN. The hodogreph gave two general fall-out areas. The lower level running from 260 degrees aroumd through south to 90 degrees with a six hour fall-out line in the directica cf the populeted atolls in the southeast quadrent about 15 to 20 miles out from ground zero. The high level redex ran from ebout 45 degrees to 80 degrees with a six hour fall-out line to 70 miles. (Since-the 6 hour fall-out lines were computed an abcut i105 cicron particle size, it vas recommended that the distance pe doubled for sefety. This atounted to considering particle sizes dovn to about 70 microns). / 2. NO change in the 72 hour cloud trajectories. 3. RadSefe Outlooks were =odified es follows; a. zikini atoll wes changed from fevcrable to unfavorable. be Eniwetok etoll remained very favereble. c. Ujelang etoll remeinec very favoreble. a=