This article is the first in a four-part blog series exploring cloud seeding and Utah’s efforts to bolster snowpack. Here, in Part One, our meteorologist introduces the fundamentals of cloud seeding — what it is, how it works and why it matters. Read Part Two to dive into why cloud seeding works well in Utah, Part Three to understand how we ensure safe and best practices and Part Four to read about common myths and misconceptions.
SALT LAKE CITY (Feb. 5, 2025) — The state of Utah has a unique challenge on its hands when it comes to water resource management. The state must balance ensuring that municipalities, farmers, ranchers and other water users have access to this precious resource while grappling with growth, planning for drought and protecting the health of Great Salt Lake. This process becomes much more challenging as the population continues to rapidly rise and climate variability occurs, stressing the resources further. We can conserve water, and we can move water around — but there’s only one way to bring additional water to the state of Utah in a safe, efficient and affordable manner, and that is by cloud seeding.
First, before cloud seeding gets mislabeled, let’s talk specifically about what cloud seeding is. Simply put, it’s just that: the seeding of clouds. Meaning, clouds must be present for cloud seeding to be effective (Figure 1). Not just any clouds, but clouds that are precipitating and have certain key properties to be identified as targets. Therefore, on those blue-sky days, when you see jet contrails at very high altitudes, that is not cloud seeding (Figure 2). Cloud seeding only occurs, again, when clouds are present, and here in the state of Utah, cloud seeding only takes place during the winter months from Nov. 1 through April 30.
Before 2022, all cloud seeding in the state of Utah was done using ground-based generators (right side of Figure 1). Ground generators are placed in locations along the foothills and higher elevations of the mountains. Relying on perpendicular winds, the material is transported up and over the mountains (Figure 3) where it interacts with what we call “supercooled liquid water”. (We’ll get into supercooled liquid water in another post.) These generators are strategically placed to ensure the best coverage and impacts for enhanced precipitation.
However, ground-based work has its limitations. Weather conditions may be favorable for cloud seeding in terms of liquid water content and temperatures, but maybe not with wind. Also, when winter inversions settle in, the stable atmosphere won’t allow the material to disperse as needed.
Thus, aircraft were added.
In 2022, one aircraft was introduced for seeding in southern Utah, while a second was introduced in 2023. However, with less than 30 hours of total flight time, it has been determined that only one aircraft is necessary at this time. That plane is stationed in St. George, Utah with a focus on the Colorado River Basin and Sevier Basin watersheds. From time to time it will make its way to Cache Valley, the Wasatch Front and even the Wasatch Back with a focus on seeding just above the winter inversion layer.
Aircraft operations take place in clouds where temperatures are measured and supercooled liquid water is detected, usually around the 13,000 feet elevation level (Figure 1). Here, single burn-in-place flares are used to distribute the material. This reacts with the cloud and enhances precipitation, leading to additional water supply for the state of Utah.
History and funding
The division administers Utah’s cloud seeding program under the direction of the state Legislature, which provides funding and policy guidance. Established as a strategic water management tool back in the 1950s, this program enhances snowfall in key watersheds to support water supplies. Our team executes cloud seeding operations with scientific expertise and careful planning, ensuring responsible and effective implementation. This is a targeted effort to maximize water resources in alignment with legislative directives and proven methodologies.
In the next blog post of this series, we’ll discuss why we cloud seed and why this process is effective in the state of Utah. We’ll also get into the benefits of cloud seeding and address some misconceptions in future, additional posts.
About the author
Jonathan Jennings joined the Utah Division of Water Resources in 2024, bringing with him an impressive 13 years of experience in cloud seeding operations. His expertise spans multiple states, including Texas, New Mexico, Arizona and Utah, where he successfully managed operational cloud seeding projects and conducted feasibility studies. Jonathan’s contributions go beyond operations — he has played a pivotal role in developing and manufacturing seeding flares, advancing cloud seeding research and leading impactful educational outreach efforts. He also serves as the President of the Weather Modification Association where he is also certified as an Cloud Seeding Operator and a Manager. A Pennsylvania native, Jonathan earned his Bachelor of Science degree in meteorology from Penn West University in 2008. Now, he’s focused on helping elevate Utah’s cloud seeding program, applying his vast knowledge to ensure continued success and innovation.
