Learn Whether Cloud Seeding Can Kill Hurricanes

How Science Can Modify Hurricanes

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Efforts at storm modification date back to the 1940s, when Dr. Irwin Langmuir and a team of scientist from General Electric explored the possibility of using ice crystals to weaken storms. This was Project Cirrus. Enthusiasm about this project, combined with devastation from a series of hurricanes that made landfall, prompted the U.S. federal government to appoint a Presidential Commission to investigate storm modification.

What Was Project Stormfury? 

Project Stormfury was a research program for hurricane modification that was active between 1962 and 1983. The Stormfury hypothesis was that seeding the first rain band outside of the eyewall clouds with silver iodide (AgI) would cause supercooled water to turn into ice. This would release heat, which would cause the clouds to grow faster, pulling in air that would otherwise reach the wall of clouds around the eye. The plan was to cut off the air supply feeding the original eyewall, which would cause it to fade away while a second, wider eyewall would grow further from out from the storm's center. Because the wall would be wider, air spiraling into the clouds would be slower. The partial conservation of angular momentum was intended to decrease the force of the strongest winds. At the same time the cloud seeding theory was being developed, a group at the Navy Weapons Center in California was developing new seeding generators that could release large amounts of silver iodide crystals into storms.

Hurricanes That Were Seeded With Silver Iodide

In 1961, the eyewall of Hurricane Esther was seeded with silver iodide. The hurricane stopped growing and showed signs of possible weakening. Hurricane Beulah was seeded in 1963, again with some encouraging results. Two hurricanes were then seeded with massive quantities of silver iodide. The first storm (Hurricane Debbie, 1969) weakened temporarily after being seeded five times. No significant effect was detected on the second storm (Hurricane Ginger, 1971). Later analysis of the 1969 storm suggested that the storm would have weakened with or without the seeding, as part of the normal eyewall replacement process.​

Discontinuing the Seeding Program

Budget cuts and lack of definitive success led to the discontinuation of the hurricane seeding program. In the end, it was decided that funding would be better spent learning more about how hurricanes work and in finding ways to better prepare for and lessen the damage from natural storms. Even if it turned out cloud seeding or other artificial measures could lessen the intensity of the storms, there was considerable debate about where on their course the storms would be altered and concern over the ecological implications of changing the storms.