TM 3-6665-304-10
calculate the downwind distance of Zones I and II Zone II is twice that of Zone I.
g. Using GZ as center, draw arcs between the two radical lines with radii equal to the two downwind distances.
h. Draw tangent lines from the cloud radius semicircle of yield group selected (b above) to the points of intersection
between radial lines and Zone I arc.
i.
Darken perimeter of fallout zones with a grease pencil to emphasize the area of hazard Label the zones.
j. Estimate downwind distances for fallout times-of-arrival after burst (H-hour) by multiplying the effective
windspeed by the hour of interest. Fallout time-of-arrival at a specific distance from GZ is estimated by dividing that
distance by the effective windspeed.
k. Draw as many dashed arcs for time-of-arrival distances (j above) as will fall within the predicted zones. Label
each time-of-arrival arc as hours after H-hour. If a time-of-arrival arc coincides with a zone boundary, extend the zone
boundary with a dashed line and label it with the appropriate time of arrival.
I. Place the area predictor on the map so that GZ on the predictor is over the actual or assumed GZ point on the
map Rotate the area
2-5
