Project Stormfury - Project Stormfury

Project Stormfury

Robert Simpson became its first director, serving in this capacity until 1965. There were several guidelines used in selecting which storms to seed. The hurricane had to have a less than 10 percent chance of approaching inhabited land within a day; it had to be within range of the seeding aircraft; and it had to be a fairly intense storm with a well-formed eye. The primary effect of these criteria was to make possible seeding targets extremely rare.

No suitable storms formed in the 1962 season. Next year, Stormfury began by conducting experiments on cumulus clouds. From August 17 to 20 of that year, experiments were conducted in 11 clouds, of which six were seeded and five were controls. In five of the six seeded clouds, changes were observed that were consistent with the working hypothesis.

On August 23, 1963, Hurricane Beulah was the site of the next seeding attempt. It had an indistinct eyewall. In addition, mistakes were made, as the seedings of silver iodide were dropped in the wrong places. As a consequence, nothing happened. The next day, another attempt was made, and the seeders hit their targets. The eyewall was observed to fall apart and be replaced by another eyewall with a larger radius. The sustained winds also fell by twenty percent. All in all, the results of the experiments on Beulah were "encouraging but inconclusive."

In the six years after Beulah, no seedings were conducted for several different reasons. In 1964, measurement and observation equipment was not ready to be used. The year after that, all flights were used for additional experimentation in non-hurricane clouds.

Joanne Simpson became its director beginning in 1965. While out to sea in August of the 1965 Atlantic hurricane season, Stormfury meteorologists decided that Hurricane Betsy was a good candidate for seeding. However, the storm immediately swung towards land, and on September 1, the planned flights were canceled. For some reason, the press was not notified that there were no seedings, and several newspapers reported that it had begun. As Betsy passed close to the Bahamas and smashed into southern Florida, the public and Congress thought that seeding was underway and blamed Stormfury. It took two months for Stormfury officials to convince Congress that Betsy was not seeded, and the project was allowed to continue. A second candidate, Hurricane Elena, stayed too far out to sea.

After Betsy, two other hurricanes came close to being seeded. Hurricane Faith was considered a likely candidate, but it stayed out of range of the seeding planes. That same year, recon flights were conducted into Hurricane Inez, but there were no seedings. Both the 1967 and 1968 seasons were inactive. Because of that, there were no suitable seeding targets in either of those two seasons.

Dr. R. Cecil Gentry became the director of Stormfury in 1968. There were no more near-seedings until 1969. In the interim, equipment was improved. What once was the primitive method of hand-dumping dry ice was replaced with rocket canisters loaded with silver iodide, and then gun-like devices mounted on the wings of the airplanes that fired silver iodide into the clouds. Observation equipment was improved. Additional reconnaissance data was utilized to modify the working hypothesis. The new theory took cumulus towers outside the eyewall into account. According to the revised theory, by seeding the towers, latent heat would be released. This would trigger the start of new convection, which would then cause a new eyewall. Since the new eyewall was outside the original one, the first eyewall would be choked off of energy and fall apart. In addition, since the new eyewall was broader than the old one, the winds would be lower due to a less sharp pressure difference.

Hurricane Debbie provided the best opportunity to test the underpinnings of Project Stormfury. In many ways it was the perfect storm for seeding: it did not threaten any land; it passed within range of seeding aircraft; and was intense with a distinct eye. On August 18 and again on August 20, thirteen planes flew out to the storm to monitor and seed it. On the first day, windspeeds fell by 31%. On the second day, windspeeds fell by 18%. Both changes were consistent with Stormfury's working hypothesis. Indeed, the results were so encouraging that "a greatly expanded research program was planned." Among other conclusions was the need for frequent seeding at close to hourly intervals.

The 1970 and 1971 seasons provided no suitable seeding candidates. Despite this, flights were conducted into Hurricane Ginger. Ginger was not a suitable storm for seeding, due to its diffuse, indistinct nature. The seeding had no effect. Ginger was the last seeding done by Project Stormfury.