Topic: seeding thunderstorms - benefits or not?

[Mike]

There's been many experiments with 'seeding' of thunderstorms to initiate rain or suppress hail within thunderstorms.

 Would members like to comment on their views as to whether it's interference with nature to take its own course or whether it really does benefit when severe weather is threatening to lesson possible damage to property or should seeding take place to initiate further rain to form within thunderstorms to benefit us?

Seeding suppresses or enhances many things within the storm - is the cost of 'bombing' the clouds worth the attempt to increase or decrease the potential of rain and severe weatherl?

Here's a photo of a seeded thunderstorm - in fact a decent shelf cloud! * courtesy of http://www.swtrea.org/photo_album.htm

Mike

[Jimmy Deguara]

Mike,

I personally do not like to play around with nature - particularly with regards to copious amounts of energy.

With regards to this specific thunderstorm, what evidence is there that the thunderstorm formed as a result of cloud seeding or of its own accord? What about the impact on other regions if it is successful. There will be possible legal cases in future if it is somehow proven that cloud seeding has impacted the rainfall of a particular region that it should not have.

Kind regards,

Jimmy Deguara

[Michael Bath]

There has been mention in the media last week about cloud seeding helping the Australian ski season this year. How can you know whether cloud seeding helps - there is no way to compare.  The weather systems that produced the snow and rain would have done what they did regardless.

There is also talk of seeding clouds in Southeast QLD to fill up the very low dams there.  You still need the major weather systems to pass over the target area before cloud seeding could be used.  Is there any real proof it works ?

[Mike]

It's a double edged sword.  There was also talk of seeding hurricanes to either slow or inhibit their growth before making landfall.  You'd need a C4 Galaxy fully laden with the crystals flying around for hours to do anything and then there's the debate about if it either promotes or inhibits rainfall - you certainly don't want to promote it in that situation!

 I'm not sure whether the photo of the thunderstorm is a result of the seeding - I'd take a guess and say it's after the storm had formed to see how much more rain it produced - they tend to wait until the towers are tall enough and then bomb it.

Again more questions - wouldn't they have to use dopplar radar to see if the seeding actually enhanced rainfdroplets within the storm to determine if it worked and then compare how much is a result of seeding and how much of it is natural?  How many clouds do you seed to try and cover this much area?  It's pretty hit and miss i would have thought.

Whether it works is another thing - Texas has a very lengthy history using seeding techniques to lessen the impact of often severe droughts. In the 1950's and into the 1960's, it was used extensively and both the state and federal governments even funded research and conducted impact studies when they did this.

This practice is still widespread today when droughts threaten and to the extent that a coverage area of about 37 million acres ( that's about 20% of the land area of the state!) is used as seeding projects alone!!  In today's times they seed only to enhance rainfall or when drought threatens the wellbeing of the state.  A few years ago a seeding project included an amazing 51 million acres for seeding projects.   With such a large area they work in they'e attempting to cover a hell of an area with the available cloud and storms!  But like you said Michael, does it really work?

Personally, I'm against seeding to some extent.  Leave nature to its own devices - they've done it in this country and perhaps not seen substantial results from seeding and is seeding really just a short term, stop-gap type fix for something we really don't have control over?  Then the other side of the coin is - well if it can assist in filling dams or rainfall where it's needed then why not? 

 It's a long debate...I'll hunt down some stats if possible on results before and after seeding.

NB: Found a link: It's too lengthy to post details here and it has many references from studies done and a host of literary references.  http://www.agu.org/revgeophys/czys01/node2.html 

Mike

[Karina Roberts (slavegirl)]

Im curious as to whether cloud seeding really does work, im against and for it. I live in se qld and i can tell you we are in a very dire situation waterwise(as is most of aust) and if i can be convinced that seeding actually works i will stand by the council's descision to seed come november just so that we have some water in our dams. On the other hand i think it is wrong to play around with nature, it is proven that Australia has had these prolonged periods of drought long before we settled this country and if we cloud seed will we disrupt what all the flora and fauna have come to evolve to and adapt to???

Any comments would be appreciated

Karina

[Mike]

Hey there Slavegirl23 and welcome.

Seeding won't have any adverse affect on the flora or fauna at all.  Seeding will either enhance or worsen a clouds ability to produce rain.  Seeding most often has the benefit of doing just what you posted, breaking drought affected areas, but it can also have the opposite affect in creating too much rain or actually weakening the cloud so that no rain falls!

It is expensive and time consuming and sometimes the negatives outweigh the positivesa and you'd have to make sure there were the right type of clouds first up to seed so that they would have produced precip and all seeding does is promote more of it.

They thought about doing this to hurricanes, but as we all know these things are massive and what they dropped probably would make things worse due to the high energy and inflow strength of the storms within.

I'm against it personally, but having said that, if areas do need it and there's no hope of rain at all - oops - then again if there's no rain, there's no cloud!!!

It has no ill-effect on the weather patterns, climate or anything, it's just a man-made Viagra for clouds that sometimes works, sometimes doesn't!

Mike

[Harley Pearman]

Hello

A great article on seeding thunderstorms.

Seeding thunderstorms and hurricanes with silver iodide has been very contentious and has not always been successful. Below is a brief story on the seeding of Hurricane Debbie (Author of this referenced below).

A classic experiment was with Hurricane Debbie (August 1969). The development of the hurricane was closely monitored and it was targetted for seeding.

The storm was well formed and within 1,100 kilometes of Puerto Rico (Carribean region). On August 18, five planes carrying silver iodide canisters and eight planes packed with monitoring equipment took off from air fields across Puerto Rico and headed for the Hurricane.

The planes flew into the Hurricane at an altitude of roughly 10,500 metres and dropped hundreds of canisters through the updraft towers and thunderstorm cells of this hurricane over a period of time. After 5 days of seeding the hurricane, Debbie's wind strength dropped from 112 miles per hour to 78 miles per hour (USA uses imperial measurements) which was a decrease of 30%.

The following day without seeding, winds increased back to 113 miles per hour. New seeding was then done and the wind speed diminished to 96 miles per hour (This being a 16% drop in wind speed.

Hurricanes Debbie's wind blast was found to have been reduced by up to 50% during the seeding program. This was a reasonably successful experiment.

However, Stormfury's success could not be replicated in other Hurricanes. This seemed to be a single one off success and subsequent experiments failed with other hurricanes.

Part of the failure stems from diplomatic relations between countries and concerns for having adverse impact on another country's rainfall patterns. Project Stormfury was later stopped because the risk of upsetting the rainfall patterns of another country was too great..

Hail suppression:

In 1972, the US National Centre for Atmospheric Research began a hail experiment. It was considered that hail could be managed and many seeding attempts were undertaken in NE Colorado in an area called Hail Alley. However nothing worked and the experiments were cancelled.

Lightning suppression:

Experiments were also done in the 1970s on suppressing lightning in Montana (USA). Clouds were seeded with aluminium coated thread fibres known as "Chaff". There was suggestion that Chaff could disrupt the electrical force of lightning in a thundercloud. Experiments were conducted but failed. Eventually funds dried up and experiments were cancelled.

It was concluded that attempts at controlling the power of hurricanes and thunderstorms had failed and could not be achieved.

(Taken from my book titled - Planet Earth - Storm by A. B. C. Whipple, 1989).


Harley Pearman

[Mike]

Nice post Harley.

Your post reinforces the variables for seeding.  It goes either way in negating or enhancing.  Even though they may have reduced this hurricane's power (wind0 by a certain percentage, what detriment did it have to the rainfall that may have been needed?  Cause and effect.  You know, i'm for letting nature take it's own course with regards to hurricanes. Let them do their thing, it's what the earth does and man does not need to intervene or interrupt their cycle to justify his own existence.

These storms have raged for millions of years and the cycle continues and each storm brings reneweal for something whether it be by way of rain, wind or temperature.

seed only if necessary to reduce the iimpact of dire straites otherwise i think let things take their own natural course!

Mike