Artificial decrease of precipitation

Along with the shortage of fresh water in many regions of the world, population and economy of some countries suffer from an excess of precipitation. Often the excess rainfall has the form of powerful showers that lead to catastrophic flooding, damaging agriculture, hydrotechnical objects and pose a threat to human life and health. Excess rainfall during harvest leads to a significant loss, continuous intense snowfall in winter cause problems for utilities and transport.
In studies on weather modification during more than half a century of its development  this problem drew considerable attention in the Soviet Union.
Implementation of these studies was mainly based on three reasons:
1) the intention to reduce the negative effects of heavy rains, causing floods and snowstorms;
2) the safety of the ground and air transport;
3) the need to create an enabling environment for urban residents during the festive sports and outdoor activities.
The beginning of works on the artificial reduction of rainfall in the USSR was provoqued by Chernobyl tragedy in 1986. It was vital to avoid precipitation in the 30-km zone and washout of radioactive substances in the Pripyat River and the Dnepr-River.
Roughly at the same time the work on improving weather conditions in Moscow area started in order to eliminate or decrease the rainfall intensity and duration, and, under certain conditions, scattering clouds moving towards the city during the events.

Improvement of weather conditions

Leading institutions of Roshydromet developed an effective technology to improve the weather conditions and the necessary technical means for its implementation. Russian technology of improving weather conditions is based on the results of experimental studies on specialized meteorological polygons in Moldova and the Volga-river region. Russian technology of improving weather conditions has been successfully used in 1986 to meteoprotection of 30-km area around the Chernobyl nuclear power plant, and from 1995 is used regularly in sports and holiday activities for meteoprotection of cities — Moscow, St-Petersburg, Tashkent and Astana. The use of the technology to improve weather allows to dissipate layered clouds and to stop or significantly reduce rainfall over the protected area.
From 1995 to the present time more than 50 large-scale operational works have been made on improving weather. Analysis of the results of these studies shows that even if it’s impossible to prevent precipitation completely anyway at least reduction in the time and area of precipitation and decrease in intensity from 3 to 10 times was achieved.