utilized in operational planning of RadSafe factors.
ad
began to deteriorate at “ITEN" minus 2 days.
A favorable upper wind pattern
a
i*
Ve
.
“y
4
;
i 4
yo
Tho wind pattern ot the H minus 30
with a trend towards
hours Commander's bricfing indicated FAVORASLE RadSafe fectors
CONDITIONALLY FAVORABLE,
Ab the H minus 18 hours bricfing o continued deteriore:tin
up the scheduled shot tin
of the wind pettcrn was forecast and it was decided to move
ag far as possible, from C930M to one-half hour before suivise,
by the H minus 6
would be sus-
which
hour Commander's briefing the FAVORABLE trend appeared to be one
tained,
This took into account the considerations that unfavernble northerly wind
Six hours
coempononts above 20,000 fect would remain very light for at lonst three to
aftor shot time.
All heavy fall-out (significant as a heelth hagard) was forecast
to be in a: ddtaavind cone-of 220° to 280° truc, with radial distance up to 4,0 miles,
Hoaviest concentration at upper Lovels was forecast to fall-out southwest from zero
point.
Primary fall-oub occurred cssentially according to thig pattern.
be
Howe
ever, WNIWETOK ISLAND received some delayed fall-out above oxpectation for two roaq
&
sons:
(1) light, variable wind ccnditions shove 20,000 fest gave a larger spread to
the predicted areas of fall-out southwest of zcro and, (2) already changing wind pate
vern aloft began to change move ranidily at ii plus 3 hours to a more normal trade
wind flow',
Ce
Fall-out on ships of Task Group 3.3 in the southern part of the Lagoon
and on EWIWETOK ESLAND was gonerall in two waves,
tensity up to 40 mr/hr, occurred at 1 plus 4 heurs,
The first one, with sustaincd inThe second wave, with sustained
intensities up to 100 mr/hr occurred at i plus 10 hours on Une oxtrenme southorly por-tion of the atoll,
d.
By 1730M, sufficient cloud bracking by aircraft head been donc to cable
a snap picture of boundaries te be defined for estimating probable foll-out duratio:
For distances up to 100 miles south and -north of the atoll, planes mide no contact
with the atomic cloud at 10,000 foot levels.
However, upwind (i.e., to oast and
east-southcast) of the atoll, nilanes made contact at 10,000 and 25,000 foot levels
at 1500M while « plane at 1900M, 120 miles cast of the atoll, did not moke contact.
&,
Cn the basis of the obsorved winds in the Lower 9000 fect, a forceast
was made by the RadSafe Officer of JTF-3 to Task Unit 3.1.5 (RadSafe Center) thet th
H plus LO hours wave of fall-out should commence decreasing «bt ZOOOM or about A plus
14 hours,
Pe
Ab no time did these Levels, however, reach significant preportions as
& health hazard from the standpoint of permissible cxposure Levels or from particlo
ft2