b. Between the two radial lines drawn from ground zero, and using
ground zero as center, draw two arcs with radii equal to the Zone I
and Zone II downwind distances found in Step 6 (Figure 3-8).
c. Using ground zero as center, draw a circle around ground zero with a
radius equal to the cloud radius at the selected map scale (Figure
Cloud Radius Circle
d. Draw two tangents extending from the ground zero circle to the
points of intersection of the two radial lines with the Zone I arc