1. Mick West

    Mick West Administrator Staff Member

    Cloud seeding has been done since before the 1950s , with the intent of increasing precipitation. But does it work? Research seems to indicate that yes it probably does, but only a little, and then only on average.

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  2. WeedWhacker

    WeedWhacker Senior Member

    indeed. Related info showing that the 'idea' goes back even earlier in time:


    (Just one pertinent excerpt...the entire web page is worthy of reading, and understanding):

    Of course the excerpt above involved attempts to make precipitation from only ground-based methods (before the invention of the airplane...although there were other "flying machines" prior to 1903! Hot air balloons, notably).

    I fear that in modern "parlance" the word 'seed' conjures a wrong impression in some peoples' minds.....in that we can "plant seeds" in soil, and then "grow" something. Thus, the implication that it's possible to "plant something" in clear air, and "grow" clouds. (**)

    (**) ...although, that is exactly how and more importantly, why contrails form.....but of course has nothing to do with "seeds" in that instance....only chemistry. [...]
    Last edited by a moderator: Dec 27, 2014
  3. Pete Tar

    Pete Tar Moderator Staff Member

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  4. skephu

    skephu Senior Member

    Operation Popeye in the Vietnam war was apparently a success. Wikipedia writes: "The operation seeded clouds with both silver iodide and lead iodide, resulting in the targeted areas seeing an extension of the monsoon period an average of 30 to 45 days." That sounds impressive, although I didn't find a reliable source for this statement.
  5. SR1419

    SR1419 Senior Member

    That does sound impressive but I do not see how cloud seeding can extend/effect long range weather patterns when it is designed to simply enhance precipitation in the immediate sense in any given rainstorm.

    Cloud seeding doesnt make clouds or storms it (maybe) provides incremental increases in rain already falling.
  6. muttkat68

    muttkat68 Member

    Cloud seeding was used as a weapon in Vietnam.

  7. WeedWhacker

    WeedWhacker Senior Member

    Yes, it was....dubbed "Operation Orange": colloquially...seems it had another "code-name:...."Agent Orange".

    TWO factors or 'elements' in that plan. ONE was defoliation, as explained below...another was the fact that in that region of the World it was possible to "seed" clouds in attempt to induce heavy precipitation....which would mean RAIN (not snow...too warm for snow). To induce an impediment to the so-called "enemy" (the North Vietnamese.) ...and to impede their ability to operate ground vehicles.

    Back then? This was (now deemed illegal) an attempt to use defoliants and herbicides, to destroy jungle foliage, and thus remove the "cover" that the (then "enemy") used to evade detection.

    In any event, notwithstanding the concept, and any sense of "whether or not it was Legal??" at that period of time....(or even if it was "ethical"??).

    These sorts of 'sprays' were conducted at VERY low altitudes.

    NOTHING at all to do with the more "modern" meme of so-called "chem"trails. (Although this is often brought up in the context of the so-called "chem"trail "debate", unfortunately, and inaccurately).
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  8. JDubyah

    JDubyah Member

    That's the difference with the experiment at the top of this post and the Popeye exercise: The experiment was just that, and experiment with a control area, and an experimental area. The Popeye exercise *seemed* to work, however there's no way of telling if that particular monsoon season would have been an exceptionally long one anyhow, if they hadn't seeded. That's what a lack of control does. It seems it worked compared to previous years, and against the average, but outliers do exist, and Popeye could have coincided with an outlier year. Or, it was an exceptional year made more exceptional by the 5-15% increase of cloud seeded.

    I'm not saying that's the case.. I'm sure the military was far more gung-ho with the seeding than in the experiment that was part of this post, and that a monsoon is waaay more productive in terms of potential rainfall than the areas in the experiment. But it needs to be considered that Popeye was a military exercise, and not a controlled experiment at all.
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  9. deirdre

    deirdre Moderator Staff Member

    Operation Orange/ Agent Orange had nothing to do with cloud seeding.

    or am i wrong?
  10. SR1419

    SR1419 Senior Member

    Yes it was.

    I think you're right. Operation Popeye was the cloud seeding program. And agent orange was the defoliant as @WeedWhacker mentioned
  11. skephu

    skephu Senior Member

    AFAIK Operation Popeye was conducted over several years, not just a single year.
  12. skephu

    skephu Senior Member

    There was no such thing as "Operation Orange". The defoliation operation was named "Operation Ranch Hand". This is completely distinct from the cloud seeding operation which was called "Operation Popeye".
  13. WeedWhacker

    WeedWhacker Senior Member

    YOU are entirely correct.....I had multiple brain farts, and completely conflated the "Agent Orange" compound that was sprayed as a defoliant with the other program...mixing up the various programs' "names" and designations.
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  14. Mick West

    Mick West Administrator Staff Member

    The topic here is is cloud seeding is effective. Please try to avoid introducing other topics.
  15. JDubyah

    JDubyah Member

    Yes, it was 1967-1972. I should have said 'period' rather than a particular year. They talk about how it extended the monsoon season by an average of 30-45 days, but I don't know the year-by-year breakdown of the season length that compose that average.
  16. Belfrey

    Belfrey Senior Member

    Some articles about Operation Popeye indicate that evaluations of its effects were inconclusive, and that the extensions of the monsoon season were due to tropical storms, not cloud seeding. See here for one example of a well-written article that unfortunately does not cite sources. Apparently there were analyses done, but I can't find primary sources on the topic.
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  17. SR1419

    SR1419 Senior Member

    Here is a recent article in the San Francisco paper about current cloud seeding efforts right over Mick's head :)


  18. Marin B

    Marin B Active Member

    For those like me who have little knowledge of cloud seeding, I found this FAQ publication by the Tasmania government informative. They say cloud seeding can increase rainfall by at least 5%. Seems like such a small percentage - how can they really say with certainty when they're dealing with something so variable as rainfall amounts? I was curious about how much silver iodide is used. The publication says < 1/2 tsp per square kilometer, which doesn't seem like much.

    ETA: I looked at the original post, which pretty much answers the question I asked.

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