Cloud Seeding

September 09, 2025

I thought it was appropriate after a recent blog on planting my second set of seeds that yesterday’s local newspaper carried a USA Today article responding to the July storm that dumped 20 inches (50.8 cm) of rain in parts of central Texas.  This was the equivalent of a month’s worth of rain and swelled the Guadalupe River over its banks, resulting in the death of 130 people.  As is typical for most disasters, people sought to place the blame in a variety of places.  One unexpected place was on the activity of a small startup called Rainmaker two days prior and 100 miles (160 km) away.  The flight had lasted 20 minutes and released 2.5 ounces (70 grams) of silver iodide into a set of clouds, resulting in a drizzle of less than 0.2 inches (1/2 cm) of rain on farmlands struggling with drought.  Scientists said the distance made it scientifically impossible for this cloud seeding to have played a role in the flooding.       

When I went online, I found cloud seeding is a type of weather modification that aims to change the amount or type of precipitation, mitigate hail, or disperse fog.  The usual objective is to increase rain or snow.  Cloud seeding involves dispersing particulate substances into the atmosphere to serve are the center (nuclei) that water vapor or ice condenses on.  Common agents include silver iodide, potassium iodide, and dry ice, but water attracting (hygroscopic) materials like table salt are gaining popularity.  Techniques include a static seed which encourages ice particle formation in supercooled clouds to increase precipitation or dynamic seeding which enhances cloud development through the release of latent heat.  The substance is usually dispersed by aircraft or ground-based generators, but newer approaches involve drones delivering electric charges to stimulate rainfall or infrared laser pulses aimed at inducing particle formation.  The effectiveness of cloud seeding remains a subject of debate among scientists despite decades of research.  Environmental and health impacts are considered minimal due to the low concentrations of substances used, but concerns persist.

Cloud seeding has been used as far back as the 1940’s for various purposes, including agricultural benefits, water supply augmentation, and event planning.  Eric Betterton, professor emeritus in atmospheric sciences at the University of Arizona, said “people have been worried about using silver iodide in the past, but the amounts are so small it’s insignificant . . . there are no known effects on the environment.”  The technique also has limitations.  You cannot create a storm or control the climate.  Seeding simply speeds up the natural process that causes rain or snow to fall.  As extreme weather events increase along with climate change, so do explanations offered by conspiracy theorists, including possible military involvement.  Lawmakers in several states have introduced bills to ban or restrict cloud seeding and other forms of weather modification.  Legal frameworks primarily focus on prohibiting the military or hostile use of weather modification techniques, leaving the ownership and regulation of cloud-seeding activities to national discretion. Despite skepticism and debate over its efficacy and environmental impact, cloud seeding continues to be explored and applied worldwide as a tool for weather modification.

THOUGHTS: Rainmaker’s 20-minute cloud seeding flight was part of a local program and these are usually funded by a water district or utility.  While it did not fuel the distant flooding disaster it did produce fear and legislation to ban or restrict weather modification.  As global warming increases, understanding how clouds behave and interact with our warming and ever more polluted atmosphere is why scientists want to study cloud seeding and not ban it.  Information is critical in understanding how our planet works.  The article closed, “You can’t engineer a flood.”  Act for all.  Change is coming and it starts with you.