Cloud Seeding, What is it All About?

The first property is: water in the atmosphere does not solidify at 0 degrees centigrade but at -40 degrees centigrade instead. This supercooled water (-40 degrees centigrade) solidifies when stirred or when it comes in contact with solid particles.

The second property is: vapor pressure saturation of crystals in the liquid form is lower than that of the supercooled water.

Cloud seeding utilizes this Bergeron principle. It was in 1946; however, that Vincent J, Schaefer, a scientists found out that when a solid, freezing particle like dry ice or silver iodide is added to the supercooled clouds, this facilitates the growth of the crystals, large enough to fall as precipitation or rain..

For a successful cloud seeding to occur, there are two conditions; however, that should be present: clouds and that the topmost portion of the cloud should be supercooled. Then dry ice or sliver iodide maybe introduced by a plane, or from the ground with the use of burners.

There are two general types of cloud seeding:

Static seeding

Cumulus clouds are targeted for this type of seeding. This is because they have insufficient freezing nuclei and when this is added artificially, this will enhance precipitation or rainfall.

Dynamic seeding

Massive seeding is utilized where dry ice or silver iodide is rapidly introduced into the clouds. This will then increase the cloud size causing precipitation or rainfall.

Between the two static seeding is more common, which is preferably done on mountain slopes where snow could be melted too when the rain falls after seeding. This would increase the amount of water going down into the lowlands which can be used for agricultural purposes or for power generation .

It is not as simple as it may sound however as there are certain factors that affect cloud seeding. The varied nature and type of clouds affect the procedure significantly.

There were several experiments conducted within the years, some were successful some were dismal failures.

During five summers in 1970, the Florida Cumulus Experiment (FACE) conducted cloud seeding experiments. The initial results were positive but when more specific experiments were done, the initial results were not validated.

Colorado, on the other hand, have been in the cloud seeding program or Weather Modification Program (WM) since the 1950s, and recognizes the significance of the continuous experimentation of the process. Recently after the 2000 drought, permits were awarded to several parts of the state to participate in this program. (www.cwcb.state.co.us/Watershe dProtectionFloodMitigation/Wea therModification).

These permits were governed by statutes which were promulgated to oversee the proper performance of the procedure.

Cloud seeding is man's artificial way to create rainfall. Perhaps in the near future, we would also be capable of producing clouds? It is a possibility that could be explored.

Whatever benefits we could gain from cloud seeding, these should be weighed against potential hazardous effects. We should only tamper with nature when there are no natural means to do solve our problems. It is always safe also, to do it cautiously because when nature extracts vengeance, it is without mercy!