The United Arab Emirates and Oman saw record levels of rainfall this week. The UAE, a desert nation, witnessed the heaviest rainfall in 75 years on Tuesday, with about 10 inches in one day, according to the country's National Center of Meteorology.
Cars were submerged on major highways, while the deluge flooded Dubai's international airport, disrupting flights at the world's busiest airfield for international travel.
Oman's National Committee for Emergency Management recorded about 9 inches of rain between Sunday and Wednesday, while several people were confirmed dead, including schoolchildren in a vehicle swept away by floodwaters.
Many have speculated that cloud seeding operations by the UAE were to blame for the extreme weather, though experts have said otherwise.
🛩️ What is cloud seeding?
It’s a weather modification technique that artificially re-creates how clouds naturally create rain and snow.
Normally, tiny droplets of water vapor in a cloud are attracted to things like dust, pollen or salt from the sea, which act as nuclei. When enough of these microscopic water droplets converge around these nuclei, they form ice crystals and are heavy enough to fall, creating precipitation.
Without nuclei, ice crystals cannot form, which means there won’t be any precipitation. But scientists discovered that ice crystals formed instantly around particles of silver iodide.
Cloud seeding essentially helps trigger this process in order for it to rain. Many times planes are dispatched and inject particles, like silver iodide, into clouds in the early stage of their formation to encourage rainfall.
💧 How well does cloud seeding work?
A rain-scarce region, the United Arab Emirates has invested heavily in cloud seeding. So much so that it has established a government task force known as the National Center of Meteorology (NCM), which performs around 300 cloud seeding missions a year.
While a major 2020 study found that cloud seeding works, scientists cautioned about its limitations. For instance, clouds need to be present and local winds and cloud temperatures could play a factor in its success.
UAE meteorological officials said their cloud seeding efforts can increase rainfall by anywhere from 10% to 30%. Meanwhile, in the U.S., meteorological authorities in California say rainfall can increase by 5% to 10%, while in Nevada, the Desert Research Institute says precipitation can increase by about 10%, according to Time.
While the UAE was running cloud seeding missions this week, the NCM told CNBC it hadn't seeded any clouds on Tuesday before the storm hit. The denial comes after Bloomberg reported that specialist meteorologist Ahmed Habib said the Tuesday rains stemmed partly from cloud seeding.
🌧️ Is cloud seeding to blame for the floods?
Given the low success rate of cloud seeding, it’s not likely it was responsible for the floods, according to experts.
Cloud seeding has a small, localized effect. This is important to know for two reasons.
The first is that most cloud seeding takes place in the eastern part of the UAE, far from populated areas like Dubai, likely due to air traffic control. Wired reports that it's unlikely any cloud seeding particles were active by the time the storms reached Dubai.
The second is that Oman didn’t conduct any cloud seeding prior to the storm and it saw some of the most devastating effects from the flooding, with over a dozen casualties, according to Wired.
However, it is likely that Dubai, a notoriously dry city, doesn’t have the effective drainage infrastructure in place to deal with the intense rainfall it saw this week. Experts also note a major reason is climate change. When the air is warmer, it can hold more water, leading to heavier rainfall and flooding.
"Cloud seeding is used to make recalcitrant clouds produce some rain," Roslyn Prinsley, the head of disaster solutions at the Australian National University Institute for Climate, Energy and Disaster Solutions, told Time. "The thunderstorms themselves are much more likely to have caused the extreme flooding in Dubai due to climate change-fuelled intense rainfall — as is happening across the world."