Project Stormfury was an attempt to weaken tropical cyclones by flying aircraft into them and seeding with silver iodide.
The project was run by the United States Government from 1962 to 1983.The hypothesis was that the silver iodide would cause supercooled water in the storm to freeze, disrupting the inner structure of the hurricane. This led to the seeding of several Atlantic hurricanes. However, it was later shown that this hypothesis was incorrect. In reality, it was determined most hurricanes do not contain enough supercooled water for cloud seeding to be effective. Additionally, researchers found that unseeded hurricanes often undergo the same structural changes that were expected from seeded hurricanes. This finding called Stormfury's successes into question, as the changes reported now had a natural explanation.
The last experimental flight was flown in 1971, due to a lack of candidate storms and a changeover in NOAA's fleet. More than a decade after the last modification experiment, Project Stormfury was officially canceled. Although a failure in its goal of reducing the destructiveness of hurricanes, Project Stormfury was not without merit. The observational data and storm lifecycle research generated by Stormfury helped improve meteorologists' ability to forecast the movement and intensity of future hurricanes.
Project Stormfury - Operation Order No. 1-70 [165 Pages, 5.25MB] - Two basic experiments have been proposed for Project STORMFURY operations 1969. In the Eyewall Experiment, seeding and monitoring of the changes in the structure and circulation of a well-developed hurricane will be attempted, if nature provides the proper storm at the right time and place. Hurricane seeding will be done at two-hour intervals over an eight-hour period. The rainband experiment consists of four primary objectives: namely, (1) Conduct a detailed, dynamic and thermodynamic investigation of the rainband; (2) Carry out seeding experiments to determine if the basic character of the rainband can be changed by seeding; (3) study the role the rainband plays in the total storm structure; and (4) investigate how its modification might affect the total behavior of the storm.
Project Stormfury - Operation Order No. 1-70 [150 Pages, 1.59MB] - The report is the basic directive for the conduct of several types of hurricane/weather modification experiments, utilizing aircraft from the Navy, Air Force and ESSA for STORMFURY operations. These research operations will be initiated, following a dry run training exercise, when a hurricane meets specific scientific and operational criteria.
Project Stormfury ANNUAL REPORT, 1969 - Published May 1970 [116 Pages, 6.41MB] - Project STORMFURY is a joint ESSA-Navy program of scientific experiments designed to explore the structure and dynamics of tropical storms and hurricanes and their potential for modification. It was established in 1962 with the principal objective of testing a physical model of the hurricane's energy exchange by strategic seeding with silver iodide crystals. These crystals have been dispensed by Navy aircraft using Navy-developed special pyrotechnic devices. The hypothesis calls for reducing the maximum intensity of a storm or hurricane by a measurable amount. Navy and ESSA scientists and aircraft, supplemented by those of the U.S. Air Force, have cooperated in STORMFURY experimental operations since 1962 when the Project began. Until 1969, one mature hurricane (Beulah, 1963) and two series of tropical cumulus clouds (August 1963 and July-August 1965) had been experimentally seeded in the western Atlantic and Caribbean Sea.
Project Stormfury ANNUAL REPORT, 1970 - Published May 1971 [169 Pages, 8.96MB] - Project STORMFURY is a joint Department of Commerce (NOAA) - Department of Defense (Navy) program of scientific experiments designed to explore the structure and dynamics of tropical cyclones and their potential for modification. The Project which was formally established in 1962 has as its principal objective experimentation directed towards changing the hurricane's energy exchange by strategic seeding from aircraft with silver iodide crystals. The crystals are dispensed from pyrotechnic devices developed by the U. S. Navy. The hypothesis calls for a measurable decrease in the maximum wind velocities near the center of the storm. Navy and NOAA scientists and aircraft, supplemented by those of the U.S. Air Force, have cooperated in STORMFURY experimental operations since 1962 when the Project began. The 1970 hurricane season produced no tropical cyclones which were eligible for seeding experiments. In spite of this, or perhaps because of it, the 1970 season was undoubtedly the most productive research period for Project STORMFURY to date.