Effective Downwind Message
ZULU
240600Z
ALFA
080015
BRAVO
085015
CHARLIE
090016
DELTA
100010
ECHO
110025
FOXTROT
120020
At 240730Z a nuclear burst occurred at a point estimated to be MN553298. A
measurement of the flash-to-bang time and nuclear burst cloud width
indicates an estimated yield of 16 KT.
d. Action.
Use the M5A2 Radiological Fallout Area Predictor to make a fallout
prediction. The estimated yield (16 KT) lies within the yield group CHARLIE
(5+ to 30 KT).
Therefore, use the effective downwind direction and
effective wind speed from line CHARLIE of the effective downwind message,
and use the "C" semicircle on the fallout predictor.
From the nomogram on the predictor, using a yield of 16 KT and an effective
wind speed of 16 kilometers per hour, read the downwind distance of the Zone
of Immediate Operational Concern (Zone I) to be 18 kilometers. Draw an arc
between the radial lines of the predictor at a distance of 18 kilometers
downwind from ground zero.
Double this distance, and draw a second arc
between the radial lines of the predictor at a distance of 36 kilometers
downwind from ground zero.
Draw straight lines tangent to the 30 KT cloud radius semicircle and
extending to the intersection points of the Zone I arc with the radial
lines. The area enclosed by the two lines, the 30 KT semicircle and the 18
kilometer arc, is the predicted Zone of Immediate Operational Concern (Zone
I).
The area enclosed by the 18 kilometer and 36 kilometer arcs and the
radial lines is the predicted Zone of Secondary Hazard (Zone II).
Draw a series of dashed arcs at distances equal to the product of the
effective wind speed (16 kilometers per hour) and the hours of interest
after the burst to represent the estimated times of arrival of fallout (16
kilometers at H + 1 and 32 kilometers at H + 2).
Arcs that fall outside
Zone II need not be drawn.
Draw a straight line from the center of the azimuth dial through the
effective downwind direction (90 degrees) on the azimuth dial, and label the
line grid north (GN). Place the center of the azimuth dial on the predictor
over the estimated GZ (MN553298) on the map (the scales of the map and
predictor must
3-29
CM5206
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