In 1947, Project Cirrus scientists dropped 80 pounds of dry ice into a hurricane for weather manipulation. The storm suddenly turned and hit Georgia, causing $2 million loss

In the years after World War II, scientists were becoming increasingly interested in the idea that humans might be able to change the weather. One experiment in 1947 took that idea into a hurricane, when military aircraft dropped dry ice into a storm over the Atlantic to see whether seeding its clouds could alter its behavior.

What happened next became one of the most controversial early experiments in weather modification. The hurricane suddenly changed direction and eventually struck the Georgia coast, killing one person and causing about $2 million in damage.

The experiment began with dry ice

The experiment was part of Project Cirrus, a joint effort involving General Electric Laboratories, the U.S. Navy and the Army Signal Corps. According to NOAA's Atlantic Oceanographic and Meteorological Laboratory, the idea was linked to GE scientist Vincent Schaefer, who had discovered in 1946 that dry ice could make supercooled water freeze.


Scientists wondered whether the same process could be used inside clouds. If freezing could be triggered in the right parts of a hurricane, they thought it might change the storm's clouds, rainfall and perhaps even its strength.

On the afternoon of October 13, 1947, Air Force aircraft flew toward a hurricane about 415 miles east of Jacksonville, Florida. The storm had moved away from land, which made it appear to be a relatively safe opportunity for an experiment.

A B-17 flew through the outer part of the storm while dropping crushed dry ice into the clouds. Another aircraft followed behind to observe what happened. A third plane acted as a control aircraft and carried Schaefer, who helped monitor the experiment.

The aircraft avoided the hurricane's eye and its strongest rainbands because they did not have the equipment needed to safely navigate those areas.

The hurricane suddenly turned

During the first run, the aircraft traveled more than 100 miles and released about 80 pounds of dry ice. The crews later returned to examine the clouds and carried out additional drops over a large cumulus cloud.

The scientists reported changes in the cloud formations. NOAA's account says the cloud deck below began breaking up after the first run, while the cloud top continued to grow after another seeding attempt.

The crews returned to base believing the experiment had produced interesting results. But the following day, scientists trying to locate the hurricane were in for a surprise.

The storm was nearly 100 miles west of where they expected it to be. It had made a sharp turn of about 135 degrees to the left and was moving west.

By October 15, the hurricane, known as King, reached Savannah, Georgia. One person died in the storm surge, while Georgia and South Carolina suffered roughly $2 million in damage.

Scientists were blamed for the storm

The timing of the experiment and the sudden change in direction quickly caused public anger. People believed the scientists had effectively pushed the hurricane toward the coast.

The situation became worse when GE laboratory chief Irving Langmuir said he was “99% sure” the storm had changed course because of the seeding.

But weather officials were not convinced. Weather Bureau chief Francis Reichelderfer asked three meteorologists to look for an earlier hurricane that had made a similar turn without being seeded.

They found one.

The comparison showed that hurricanes could make major changes in direction naturally. The evidence weakened the claim that the dry ice had sent King toward Georgia, and the threatened lawsuits eventually disappeared.

The idea returned years later

The 1947 episode badly damaged public confidence in hurricane modification, and scientists became cautious about discussing the idea. But the concept did not disappear completely.

In 1962, the U.S. Weather Bureau and Department of Defense began Project STORMFURY, a much larger attempt to weaken hurricanes. Instead of dry ice, scientists used silver iodide, hoping it would freeze supercooled water and encourage the storm to develop a new eyewall farther from its center.

Researchers seeded several hurricanes, including Beulah in 1963 and Debbie in 1969. Some experiments appeared to show wind reductions of 10% to 30%, which initially looked promising.

Later research, however, raised serious doubts about those results. Scientists found that hurricanes generally contain too little supercooled water for the method to work as expected. They also learned that hurricanes can naturally develop outer eyewalls and weaken through processes that looked similar to the changes researchers had attributed to seeding.

Project STORMFURY was eventually discontinued in 1983.