Did a cloud-seeding start-up really increase snowfall in part of Utah?

States like Utah in the western United States are suffering a record snow drought, raising fears of wildfires and low flow in the crucial Colorado River. But a startup that releases negatively charged aerosols that can be carried into clouds claims to have increased snowfall by 20% in a Utah mountain range.

Rain Enhancement Technologies compared snowfall in the La Sal Mountains and the Abajo Mountains, 70 kilometers to the south, during five recent dry winters. When the company was operating its high-voltage ionizing array upwind of the La Sal Mountains in January, the range received 9 centimeters more snow than would have been expected given the amount of snow the Abajo Mountains received, the company says.

But scientists warn that these results could be a result of chance and that it is too early to tell how well the technique works.

“Cloud seeding operations have been active for some time, and we’re coming up with another way to increase precipitation…but one that doesn’t involve any chemicals,” says company meteorologist Jeff Chagnon. “We don’t need to fly in the clouds either… We can just flip a switch from anywhere in the world and operate for about 48 hours at a time. »

The United Nations warns that the world is entering an era of “water bankruptcy”, with up to 3 in 4 people facing water shortage or contamination. Countries like Iran, where water shortages have helped fuel bloody protests, are trying to cause more rain by spraying salts such as silver iodide from planes. Nine U.S. states also have cloud seeding programs.

But the public has often been concerned about the unknown health effects of silver iodide released in large quantities, while conspiracy theories around “chemtrails” fuel distrust of alleged weather modification programs. Ten U.S. states have banned or considered banning cloud seeding.

Rain Enhancement Technologies passed 10,000 volts of electricity through a coiled wire suspended between a pair of 8-meter pylons. Tiny aerosols like dust, soot, or salt pick up electrons when they blow near this wire, just like your feet can pick up charges when they rub across carpet. The wind then carries some of these ionized particles to the clouds.

Water naturally condenses into aerosols in clouds to create droplets that move around and collide with each other. If they stay together, they can fall to Earth as rain. However, the droplets often do not stick and therefore remain too small for gravity to overcome the updraft that keeps them aloft.

But electrically charged droplets – even those with the same charge – interact to form polarity, with the negative side of one droplet attracting the positive side of another. When droplets condense around Rain Enhancement Technologies’ negatively charged aerosols, the attraction between them accelerates the rate of collision and coalescence that produces precipitation, according to Chagnon.

The technology cannot drive the upward movement of air that generates clouds and rain. “But once the cloud forms, we can extract a little more water from it,” explains Chagnon.

Cold War evidence suggests that electrical charge can enlarge cloud droplets. A 2020 analysis found that there was 24% more rain on the UK’s Shetland Islands on days when radioactivity from nuclear bomb tests had ionized the air.

A Rain Enhancement Technologies trial in Oman from 2013 to 2018 increased rainfall by 10 to 14 percent, depending on the statistical analysis used, a study shows. An experiment that dispersed negative ions from a similar array in China claimed to have increased precipitation by about 20 percent.

But the World Meteorological Organization warns that while the spread of salts in winter clouds has been shown to affect precipitation, the ionization approach still lacks scientific evidence.

“It’s interesting that they saw something consistent with a change in the clouds,” says Edward Gryspeerdt of Imperial College London. “But because precipitation, snowfall, and precipitation are incredibly variable, there is always a significant chance that the effect they observed occurred by chance.”

The five dry years Rain Enhancement Technologies used to establish the baseline in Utah’s mountain ranges may not be enough to fully account for the magnitude of differences seen in snowpack across seasons, says Jeff French of the University of Wyoming.

“I would wait for more experimental studies and more years to confirm the validity of ionization as an additional snow catalyst,” says Ibrahim Oroud of Mutah University in Jordan.