Cloud seeding is not a rumor and not a secret. In the United States it is a reported, permitted, contracted activity with a fifty-year paper trail; abroad it ranges from statutory transparency (Australia) to near-total opacity (China). This page is the census: every program this site can document, what kind of seeding it is, who flies or fires it, and where its records live.

Numbers below carry their class of evidence: RECORD a filed document · MEASURED an observation · MODELED a simulation · CLAIMED an operator's or government's own number. The distinction matters more on this page than anywhere else on the site.

Every non-federal U.S. project must file with NOAA before it starts RECORD — see The Records. The programs below are the operating core, largest first.

Utah — the largest U.S. program

State-supported winter seeding since 1974, run by the Division of Water Resources with North American Weather Consultants as operator. After a 2023 legislative expansion ($12M one-time plus $5M/yr RECORD), Utah now runs about 190 remotely controlled ground generators plus aerial and drone seeding — billed as the world's largest remote-controlled program CLAIMED. Season November–April, silver iodide. The state claims roughly +10% snowpack and ~200,000 acre-feet a year of added streamflow CLAIMED — target/control estimates, not a randomized result. Annual per-area reports with generator maps: water.utah.gov/cloudseeding. An independent 2026 re-evaluation from public data (Judy) found the storm-scale effect falls to +1.5% [−9.6, +13.1] once operator storm selection is designed out, with a ±6% noise floor under any seasonal claim MEASURED — worked in full as Forensic Case 002. Its by-product is the first public geocoded layer of Utah's generator network, mirrored here: /data/atlas/generators-ut-2024-25.csv (181 sites, 8 programs) with the per-area seeding timeline 1974–2026 in ut-seeding-treatment.json.

Idaho — the biggest acre-feet claims anywhere

The Idaho Collaborative Cloud Seeding Program pairs the Idaho Water Resource Board with Idaho Power, which has seeded since 2003. About 57 remote generators and three aircraft target the Payette, Boise, Wood River and Upper Snake basins, November–April RECORD. The partners claim about one million acre-feet a year combined CLAIMED — the largest published yield claim of any U.S. program. End-of-season reports: IDWR. Idaho is also where the physics was proven: the SNOWIE experiment flew here in 2017.

Texas — the biggest footprint by area

Roughly seven warm-season rain-enhancement projects over ~31 million acres — about a sixth of the state RECORD — permitted and licensed by the Texas Department of Licensing & Regulation, generally March–November. The big four: the West Texas (San Angelo), South Texas (Pleasanton), and Trans-Pecos (Fort Stockton) weather modification associations and the Panhandle Groundwater Conservation District — plus, since 2025, the venture-backed startup Rainmaker Technology Corp. on the Gulf Coast. Texas permits require newspaper notice and allow public hearings, and TDLR publishes a county-level project map.

Colorado, Wyoming, Nevada, California

Colorado: the CWCB permit program covers the San Juans, Grand Mesa, Gunnison, the Upper Colorado headwaters and ski-country programs — with built-in suspension criteria that halt seeding when snowpack runs too fat RECORD; Lower Colorado River Basin states help fund it. In late 2025 the CWCB also permitted a first-of-its-kind ionization array near Gill — "seeding" without chemicals, testing what a permit even means. Wyoming ran the field's most important U.S. randomized experiment (the $8.8M Weather Modification Pilot Project over the Medicine Bow and Sierra Madre) and has since shrunk to a ground-only program after the legislature cut airborne funding in 2025 RECORD. Nevada's Desert Research Institute program ($600K/yr since 2023) targets the Tahoe-Truckee, Ruby and Spring mountains and publishes per-season acre-feet estimates (~56,000 in 2023–24 at ~$11/acre-foot CLAIMED). California has run utility and county programs continuously since the early 1950s — PG&E on the Feather and Mokelumne, Santa Barbara County, the Kern River — catalogued in the state's Water Plan.

The hail belt

North Dakota's Cloud Modification Project has flown hail suppression and rain enhancement in the western counties since 1961 — June 1 to August 31, around the clock, flown by Weather Modification Inc. of Fargo, with annual operations reports filed publicly RECORD. Western Kansas has run a groundwater-district hail program since 1975 (~8,000 sq mi, April–September). Hail suppression is also the oldest continuous seeding tradition abroad — France's ANELFA generator network has run since 1952, Mendoza has defended its vineyards since 1959 (sixty years of reviews finding no statistically significant effect MEASURED), and Russia's North Caucasus rocket program is 65 years old.

Sources for every figure on this page are collected in the site's research corpus — NOAA filings, state permit files, program annual reports, and the primary literature. Independent market estimates put global cloud seeding at roughly $0.4–0.6B in 2025. Compiled September 2026; programs change yearly and this page will track them. The atlas is also published as data: /data/atlas/programs.json — 37 geocoded programs across 14 countries, each with type, operator, season, status and evidence-classed claims. The winter programs from this file are the silver rings on the Seedability map. For Utah, the atlas goes a level deeper: generators-ut-2024-25.csv (181 generator sites) and ut-seeding-treatment.json (per-area adoption timeline 1974–2026), mirrored with attribution from Judy 2026.