Hurricane Esther Tamed: Project Stormfury Begins

The United States National Hurricane Research Project dropped eight cylinders of silver iodide into the eyewall of Hurricane Esther on September 16, 1961, producing a measurable 10 percent reduction in wind speed and launching one of the most ambitious weather modification programs in American history. The experiment, conducted by aircraft that flew directly into the hurricane's eyewall at roughly 10,000 feet, was based on the hypothesis that seeding clouds with silver iodide would create additional ice crystals that would disrupt the storm's internal convection cycle and weaken it from the inside. The initial results seemed to confirm the theory, and the success led directly to the establishment of Project Stormfury, a joint initiative between the National Oceanic and Atmospheric Administration and the U.S. Navy that ran from 1962 to 1983. Stormfury conducted seeding experiments on several Atlantic hurricanes over the following two decades, producing ambiguous results that scientists debated intensely. The fundamental problem was distinguishing the effects of the seeding from natural fluctuations in hurricane intensity that occur regardless of human intervention. By the late 1970s, improved understanding of hurricane dynamics revealed that tropical cyclones contain far less supercooled water than the seeding hypothesis required, making it unlikely that silver iodide could produce meaningful changes in storm strength. Project Stormfury was quietly discontinued. The program remains a fascinating episode in the history of humanity's attempts to control weather, and the scientific data it generated contributed significantly to modern hurricane forecasting models.