Project STORMFURY was an ambitious experimental
program of research on hurricane modification carried out between
1962 and 1983. The proposed modification technique involved
artificial stimulation of convection outside the eyewall through
seeding with silver iodide. The invigorated convection, it was
argued, would compete with the original eyewall, lead to reformation
of the eyewall at larger radius, and thus, through partial
conservation of angular momentum, produce a decrease in the
Since a hurricane's destructive potential increases rapidly as
its strongest winds become stronger, a reduction as small as 10%
would have been worthwhile. Modification was attempted in four
hurricanes on eight different days. On four of these days, the winds
decreased by between 10 and 30%, The lack of response on the other
days was interpreted to be the result of faulty execution of the
seeding or of poorly selected subjects.
These promising results came into question in the mid-1980s
because observations in unmodified hurricanes indicated:
- That cloud seeding had little prospect of success because
hurricanes contained too much natural ice and too little
- That the positive results inferred from the seeding
experiments in the 1960s stemmed from inability to discriminate
between the expected results of human intervention and the natural
behavior of hurricanes.
ReferenceWilloughby, H. E., D. P. Jorgensen, R. A. Black,
and S. L. Rosenthal, 1985: Project STORMFURY, A Scientific
Chronicle, 1962-1983, Bull. Amer. Meteor. Soc.,
to History page.
to Modification page.