Being a pilot is an exciting job whether you’re flying for an airline or… helping control the weather. Well, not really controlling it, but rather influencing it. And how can a pilot help influence the weather? By cloud seeding. But what is it?
Simply put, it is a process of combining different kinds of chemical agents, such as silver iodide, dry ice and common table salt, with clouds. This chemical and salt concoction mixed with clouds should thicken the clouds and increase the chance of rain or snow. The chemicals are either shot into the clouds or released onto the clouds by flying near and into them.
According to the World Meteorological Organization, at least 56 countries have engaged in cloud seeding as of 2016. This includes United Arab Emirates that try to decrease the water demand, and China, who tried to stop the massive rainfall for the 2008 Olympic opening ceremony with cloud seeding by speeding up the water cycle.
So, how does it actually work?
As we probably learned in school, when water evaporates and rises into the atmosphere, it is in a gas form. After some time, this water vapor cools off and condenses into clouds. However, to condense, the vaper needs to attach itself onto something. And that something is water or ice crystals. As more water condenses onto the vapor, the droplets get heavier and eventually fall as rain. If the cloud is below freezing point of water, and the precipitation falls to a below freezing point air – you get snow.
Cloud seeding is basically trying to urge condensation of water and make the water stick onto these newly introduced particles, like silver iodine, or to form more ice crystals by cooling the clouds’ temperatures. The usual intent is to increase precipitation (rain or snow), but hail and fog suppression are also widely practiced in airports, where harsh weather conditions are experienced.
Is it effective?
A recent research in Idaho has showed some proof of it. During a cloud seeding flight, a plane flew in laps around potential clouds between two ground-based radars while dropping canisters of silver iodine. The same plane also flew through the clouds, streaming the silver iodine from its wings. For some time, the installed ground sensors did not show any results. But then, the silver iodine laced cloud lines appeared. Water droplets were mixing with the silver iodine, freezing and then eventually they were heavy enough to drop.
Working as a cloud seeding pilot is a rewarding job: knowing that you provide rainfall for those in need, or by dispersing fogs and suppressing hail in airports, helping save time for both airlines and passengers.