WE'VE had rainmakers-now say hello to the rain-busters. Storm experts in the US have plucked a cloud from the sky for the first time.
By sprinkling a water-absorbing powder over the cloud, the researchers made it disappear from the sky and weather station radar screens. They hope the powder will one day dry up deadly hurricanes and tropical storms.
"It is the moisture that gives hurricanes their strength," says Peter Cordani who runs Dyn-O-Mat, the company that makes the product. "In the case of a huge hurricane, we would not be trying to soak it up altogether. But what we would do is break it up and reduce its strength and killing potential. We think we can save lives with this product and we are very happy about that." The powder could also banish rain over open-air events and sports fixtures.
Cordani and his team hope to get government permission to tackle a hurricane or tropical storm in the coming season.
In their latest experiment, large military aircraft scattered the powder through a storm cloud 1600 metres long and over 4000 metres deep. It took about 4000 kilograms of powder to soak up the moisture from the cloud, making it virtually disappear. "I had calls from a weather tower and even from Channel 5 news in Miami, saying that they had seen the cloud literally disappear off the radar screen. They confirmed that there had been a tall build-up and the next moment it was gone," Cordani says.
Each grain of the powder, called Dyn-O-Gel, is capable of absorbing 2000 times its weight in moisture, condensation and rain. Each molecule of powder can hold several molecules of water. The wet powder becomes a gel.
The shape of the grains is also crucial for maximum absorption of moisture. "If you were to look at a grain under a microscope, it would look rather like a cornflake," says Cordani. "This means that they flutter back and forth like a snowflake as they pass through the cloud, taking up as much moisture as possible. The first polymer we made just went straight down through the cloud," he says. Once the polymer turns into a gel, it becomes heavier and falls to earth. The gel dissolves when it hits salt water, so if possible, storm clouds will be tackled over the ocean. But the gel should still be safe if it falls over land. "Much of the gel evaporates on the way down, and it is biodegradable and not hazardous to the environment or anybody's health," says Cordani. The company spent $1 million on the test, and hopes to sell their powder to the US government.
The same powder can also be used to help make rain. The tiny flakes help bind rain drops together, stopping them from evaporating as quickly. Once the powder is turned into a water-laden gel you could also use it to fight fires by dousing the flames.
So, can we have sunny days whenever we like? Maybe. "If there was a 50-mile storm front moving in, we could only put holes in it. It would just keep coming," says Cordani. But "if there was a cloud threatening a sports fixture, it would be possible to get rid of it".
Author: Marina Murphy
New Scientist issue: 4TH August 2001
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