Cloud Seeding During the Vietnam War
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Project Popeye was a highly classified weather modification program in Southeast Asia during 1967–1972. The objective of the program was to produce sufficient rainfall along these lines of communication to interdict or at least interfere with truck traffic between North and South Vietnam.
A test phase of Project Popeye was approved by State and Defense and conducted during October 1966 in a strip of the Lao Panhandle generally east of the Bolovens Plateau in the valley of the Se Kong River. The test was conducted without consultation with Lao authorities (but with Ambassador Sullivan’s knowledge and concurrence). |
Image by James K. F. Dung on Wikimedia Commons
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During the test phase, more than 50 cloud seeding experiments were conducted. The results are viewed by DOD as outstandingly successful.
The experiments were deemed undeniably successful, indicating that, at least under weather and terrain conditions such as those involved, the U.S. Government has realized a capability of significant weather modification. If anything, the tests were “too successful”—neither the volume of induced rainfall nor the extent of area affected can be precisely predicted (Department of State - Office of the Historian, 1967).
- 82% of the clouds seeded produced rain within a brief period after seeding—a percentage appreciably higher than normal expectation in the absence of seeding.
- The amount of rainfall induced by seeding is believed to have been sufficient to have contributed substantially to rendering vehicular routes in this area inoperable. Since the end of the rainy season, the communists have failed to undertake route repairs and there has been no vehicular traffic.
- In one instance, the rainfall continued as the cloud moved eastward across the Vietnam border and inundated a U.S. Special Forces camp with nine inches of rain in four hours.
- DOD scientists consider that the experiment demonstrated a capacity to raise and maintain rainfall under controlled conditions to the level at which the land is saturated over a sustained period, slowing movement on foot and rendering the operation of vehicles impracticable.
The experiments were deemed undeniably successful, indicating that, at least under weather and terrain conditions such as those involved, the U.S. Government has realized a capability of significant weather modification. If anything, the tests were “too successful”—neither the volume of induced rainfall nor the extent of area affected can be precisely predicted (Department of State - Office of the Historian, 1967).
References
Department of State - Office of the Historian. (1967). Foreign Relations of the United States, 1964–1968, Volume XXVIII, Laos - Office of the Historian. [online] Available at: https://history.state.gov/historicaldocuments/frus1964-68v28/d274#fnref:1.5.4.4.14.336.7.6 [Accessed 12 Sep. 2017].