Cloud seeding in Utah

Storms moving across the Great Basin hit the Wasatch Range and are forced upward. That orographic lift produces exactly the ingredient seeding depends on: supercooled liquid water in cold clouds over terrain. A meaningful share of that water passes over the range without ever converting to snow.

The same geography that makes the Wasatch a reliable snow producer also makes it a well-defined target. Storm tracks are relatively consistent, the catchments that feed the valleys are mapped, and the relationship between high-elevation snowpack and downstream supply is well understood.

Snowpack functions as a reservoir that requires no construction. It stores winter precipitation and releases it gradually through spring and early summer, when demand rises. A weak snow year does not just mean less water — it means water arriving earlier and faster, which is harder to capture and store.

For water managers, the value of seeding is not a single storm. It is a possible percentage improvement in seasonal precipitation, evaluated over multiple winters, alongside conservation and storage. It is one tool in a portfolio, and it should be presented that way.

• Water districts and municipalities. Inflow to reservoirs is the operating number. Additional snow-water equivalent in the contributing basins is directly relevant.
• Ski resorts. Natural snowfall reduces the hours, water, and energy spent on snowmaking, and affects season length and conditions.
• Agriculture. Irrigated acreage across the state depends on runoff volume and timing.
• The Great Salt Lake. The lake is the terminal point of these watersheds. Its level reflects what reaches it after upstream use — which is why watershed inflow is part of any serious conversation about lake recovery, alongside conservation and allocation.

Weather modification in the United States is a regulated activity. Operators are generally subject to state-level permitting or registration requirements and federal reporting for weather modification activities, and any flight operation is additionally subject to aviation rules and airspace coordination. Requirements vary by state and by program, and we describe our own authorizations specifically rather than generally when discussing a project.

Mountain terrain is the hardest environment for both of the traditional delivery methods. Ground generators depend on uncertain vertical transport over complex topography; crewed aircraft face icing and terrain risk in winter storms at night. Uncrewed aircraft can place material in the cloud, over the intended catchment, without putting a crew in those conditions — and can bring back the flight and atmospheric data that lets a district evaluate the program.

More on drone cloud seeding, the underlying science, or common questions and answers.