San José, Costa Rica, since 1956

Could cloud seeding help Costa Rica during dry season?

Experts from the Costa Rican Electricity Institute (ICE) are assessing the possibility of provoking rain when dry season conditions lead to a depletion of hydroelectric reservoirs.

To avoid blackouts and keep costs down, experts are performing meteorological measurements to define if the use of technology to cause rainfall would be necessary.

The procedure, known as cloud seeding, consists in using aircraft to release and ignite flares containing silver iodide into clouds, Federico Gómez Delgado, director of ICE’s Engineering Studies Department, told The Tico Times. 

Silver iodide creates condensation nuclei (crystals in which moisture condenses) in a cloud, causing water droplets suspended in the atmosphere to adhere to them, and causing the cloud to grow more than it would in normal conditions, creating a chain reaction.

According to the National Meteorological Institute, or IMN, October ended with critically low water levels at major reservoirs throughout the country.

At Arenal, in the northwestern province of Guanacaste, the IMN reported 35 percent less than average water in the local reservoir. In Cachí, in Cartago, officials noted 40 percent less than normal, while at Angostura, in Turrialba, there was a 35 percent decrease. If dry season conditions continue, the cost of producing electricity – and rates charged to consumers – will increase.

Delgado said that based on a cloud-seeding program developed from July-November in 1994 and carried out by U.S. company Atmospherics Incorporated, results showed the technique produced increases of some 10 percent in the Arenal reservoir. At the time, the Costa Rican government paid ₡110 million ($220,000) to the California-based company to test the process.

He also said cloud seeding would require hiring an external company with experience and the appropriate equipment, such as airplanes and weather radars, which ICE currently does not own.

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