AAA has committed up to $400,000 to a new drought-response program over the Carraízo and La Plata watersheds. The final report from Puerto Rico’s previous effort found that only four of 27 seeding events had significant or moderate effects.
Puerto Rico’s water utility has hired the same cloud-seeding contractor it used during the 2015 drought, despite a final report that found the earlier program had limited success producing rain and runoff.
The Puerto Rico Aqueduct and Sewer Authority, known as AAA, issued an emergency purchase notification on August 19; a purchase order dated August 22 set the contract at up to $400,000 for Seeding Operations and Atmospheric Research, or SOAR. The contract covers operations over the watersheds of the Carraízo and La Plata reservoirs and runs through November, according to documents reviewed by El Nuevo Día. The first flight took place September 5.
The program began as drought conditions continued to affect water service across metropolitan San Juan. Reuters reported on August 6 that nearly 68 percent of Puerto Rico was in drought and that San Juan had recorded its driest July on record, according to the National Weather Service. Rotating 48-hour rationing was imposed for customers in seven municipalities served by Carraízo, including San Juan.
Gov. Jenniffer González Colón has also identified Cidra as a reservoir requiring attention. Cidra is part of the administration’s broader drought discussion, but the SOAR contract reviewed by El Nuevo Día specifically names the Carraízo and La Plata watersheds.
The 2026 cloud seeding contract
Cloud seeding attempts to increase precipitation from clouds that already contain suitable moisture and temperature conditions. It cannot create clouds or manufacture water vapor.
Aircraft typically release small particles into selected clouds. Silver iodide can encourage ice formation in colder portions of a cloud, while hygroscopic salts can promote the growth and collision of water droplets in warmer clouds. Current Puerto Rico reporting says the 2026 operation may use silver iodide or calcium chloride depending on atmospheric conditions.
SOAR’s contract requires the company to prepare reports on its operations and results, Primera Hora reported. AAA has said it will evaluate the information and disclose it to the public.
Results of the 2015 program
Puerto Rico used SOAR during the severe drought of 2015. The earlier operation also involved Carraízo, La Plata and Cidra and was carried out with the approval of the government’s Drought Technical Committee.
A 144-page final report evaluated 27 seeding events. El Nuevo Día reported in June 2016 that only one event was classified as having a significant effect, three had moderate effects, 16 had minimal effects and seven had no effect. The single event rated significant was associated with as much as 0.80 inches of rain.
The report concluded that the available data showed limited effectiveness in inducing rainfall and runoff. El Nuevo Día’s 2016 account appeared under the headline “Un fiasco la siembra de nubes,” or “Cloud seeding a fiasco.”
The Puerto Rico Planning Board later reported that the 2015 operation cost an average of $66,500 per month, excluding fuel and seeding materials. Its 2018 Economic Report to the Governor said AAA had not made the results public. A final project report nevertheless existed and was covered by El Nuevo Día, making the more precise issue whether AAA itself formally released and explained the findings.
Disclosure of the new operation
Pablo Méndez Lázaro, an environmental scientist who served on the 2015 Drought Technical Committee, has contrasted the public handling of the two programs.
Méndez Lázaro told El Nuevo Día that the earlier effort was conducted “públicamente… con transparencia.” He said the 2026 process has involved less disclosure: “ha habido un secreto al momento de hacer estas gestiones.”
The August 19 emergency purchase notification, the September 5 start date and the contract terms became publicly known through reporting after the program was underway. AAA’s commitment to release SOAR’s operational reports now creates a measurable disclosure standard for the agency.
Useful records would include each flight’s date, route and target area; the cloud conditions used to authorize seeding; the material and quantity released; radar and rain-gauge measurements; and the method used to estimate how much precipitation would have occurred without intervention. Reservoir inflow should be reported separately from rainfall because not all rain over or near a watershed reaches the reservoir.
AAA defends the program
AAA President Luis González Delgado has defended cloud seeding as a scientifically grounded method used in other jurisdictions. He told El Nuevo Día that the utility has a responsibility to evaluate tools that are responsible and viable as it responds to the drought.
The 2015 findings do not establish that every future operation will fail. Cloud conditions vary from flight to flight, and the earlier report recorded at least some effect in four of 27 events. They do establish a demanding local benchmark for the new contract: most of the earlier seeding events were classified as having minimal or no effect.
AAA has not said that cloud seeding will replace reservoir management, infrastructure repairs or conservation measures. The administration has presented it as an additional drought-response tool.
Findings from the federal review
A December 2024 assessment by the U.S. Government Accountability Office found that studies estimated cloud seeding produced between zero and 20 percent additional precipitation. GAO cautioned that suitable clouds must already exist and that the overall benefits remain difficult to prove because natural weather varies and controlled comparisons are difficult.
The range does not mean the Puerto Rico program will generate 20 percent more rainfall. A local evaluation would need to measure individual missions and the resulting runoff under Puerto Rico’s atmospheric and watershed conditions.
GAO also reviewed questions surrounding silver iodide. Limited available research did not indicate an environmental or human-health concern at concentrations used in current operations, but the agency said the effects of wider use remain uncertain.
Reporting and evaluation
Federal law requires people or organizations conducting weather-modification activities in the United States and its territories to report the projects to the U.S. Department of Commerce. GAO has found shortcomings in the completeness of federal weather-modification records and recommended improved reporting of seeding agents and project results.
AAA’s promised public release will determine how closely the 2026 program can be compared with the 2015 final report. A complete evaluation would allow the public to see how many flights were attempted, how many clouds were treated, how the results were classified and what the utility paid for each measurable outcome.
The new program is scheduled to continue through November. Its value will depend on both the weather encountered over Carraízo and La Plata and the quality of the evidence AAA publishes after the flights.
Related coverage: Carraízo rationing suspended indefinitely | Puerto Rico still nearly 40% in extreme drought despite rationing pause
Sources: AAA; El Nuevo Día; Primera Hora; Reuters; Puerto Rico Planning Board; U.S. Government Accountability Office; U.S. Drought Monitor; National Weather Service; and 15 U.S.C. Chapter 9A.
