A Summary of Rain Enhancement Operations in Texas
Many countries and several western states have had cloud seeding operations for decades. The history of Texans using cloud seeding to lessen the impact of periodic, often severe, droughts is lengthy and fascinating. Numerous “rainmaking” efforts sprouted during the epic drought of the 1950s, and some continued into the 1960s, giving impetus to the Texas Legislature to adopt a law, in 1967, governing the use of weather modification technologies. In ensuing years, both the State and federal governments provided funds for both cloud seeding research and assessing the impact of commercial weather modification projects.
With more substantive evidence that cloud seeding could invigorate convective clouds—promoting their growth and capacity to produce rainwater—a coordinated, State-funded program began in earnest in the latter half of the 1990s. Today, with drought a pending, if not ever-present, threat to the economy and well-being of Texans, rain enhancement projects flourish within large areas of Northwest, West, and South Texas. In fact, the five cloud seeding projects today cover about 31 million acres (or about one-sixth of the land area of the state)..
Texas’ present-day cloud seeding efforts are much more than well-considered responses to drought, however. They are also concerted efforts, using the latest technological tools and understanding, to replenish fresh-water supplies in aquifers and reservoirs as well as to help meet the growing needs of agriculture, industry, and municipalities for fresh water. Political subdivisions like water conservation districts and county commissions have embraced the technology of rain enhancement as one element of a long-term, water-management strategy designed to ensure a growing population has enough water to meet its future needs.
Each of the cloud seeding projects uses specially-equipped aircraft designed to place seeding materials (in the form of pyrotechnic devices, or flares, containing silver iodide and other compounds) into convective towers (turrets of growing thunderstorms) to induce them to expand and process more atmospheric water. The seeding is achieved by burning flares either mounted on the wings of single and twin-engine aircraft or held in racks, and dropped (ejected), from the underside of the aircraft fuselage. Pilots in the aircraft are directed to convective clouds believed by the meteorologist to be treatable with the seeding agent. Timing and targeting are the two critical factors in successful seeding of young thunderstorms. The concerted efforts of both pilot(s) and meteorologist are designed to give the growing cloud a “nudge” to enable it to be more efficient in the way it uses available cloud droplets to grow raindrops.
Projects in Texas
At one time, State matching funds were allocated to the sponsoring groups to enable them to procure needed hardware such as specially-equipped aircraft and ground-based radar systems. Each project initially constructed its program, either leasing or purchasing aircraft, at a cost of 8 to 9 cents per acre, with the State assuming up to 4.5 cents of that cost. Eventually, the State share of the cost declined, and today no residual State funds are used to sustain these programs. From the time the State began paying in part for the programs (1997) until State funds were exhausted (2004), the State contributed about $11.7 million. An additional $1.5 million in State funds was spent during that time to assess the projects’ performance.
Rain enhancement projects are currently being funded exclusively by underground water conservation districts and other local political subdivisions like county commissions and aquifer authorities.
The following is a description, by project, of rain enhancement operations being conducted in Texas. Details of specific operations and reports can be found at the each association’s link.
West Texas Weather Modification Association (WTWMA)
This project, based in San Angelo, was established in 1995. Its target is the third largest in the state---some 6.4 million acres in west central Texas between Midland and San Angelo. The WTWMA employs a full-time meteorologist and pilots using Doppler weather radar data produced by the National Weather Service at Mathis Field.
The project has a dual purpose: Permits are held by the WTWMA for both rain enhancement and hail suppression operations. The way in which the Association obtained its aircraft and radar, and hired its permanent staff, in 1997-98, to become self-contained as a project served as a prototype for other rain enhancement programs that materialized in Texas in subsequent years. The staff of the WTWMA can provide more information about this project (325-949-1950); West Texas Weather Modification Association).
South Texas Weather Modification Association (STWMA)
The project has its base of operations in Pleasanton (south of San Antonio) was established in 1997 to seed clouds over a target area extending from the base of the Edwards Plateau to near the coastal bend area of Texas. The STWMA is an alliance of two water districts (Evergreen Underground Water Conservation District and the Live Oak Underground Water Conservation District) and a county commission. Seeding activities are directed by a staff meteorologist working with National Weather Service Doppler weather radar data from the airport in Pleasanton.
In 2002 the STWMA expanded its target area to absorb three of the counties previously in the cloud seeding target area of the rain enhancement program of the Edwards Aquifer Authority (EAA). The EAA reduced the size of its target area (now the primary drainage area for the Edwards Aquifer) and enlisted existing rain enhancement projects based in Pleasanton to provide aerial and technical coverage for its redefined area. As a result, the target area of the STWMA expanded by some 2.2 million acres, to nearly 6 million, making it the state’s second largest weather modification target. The EAA contracts with the STWMA for cloud seeding services in Bandera, Bexar, and Medina counties. More information on this project can be obtained by contacting the STWMA staff; Additional information regarding operations: South Texas Weather Modification.
Panhandle Groundwater Conservation District (PGWCD)
One of the largest water conservation districts in Texas also conducts cloud seeding operations to enhance rainfall and, thus, augment groundwater recharge over the Ogallala Aquifer in the state’s northern extremity. The District was created by legislature in 1955, and it began operating in 1956 in portions of Gray, Carson, Potter, and Armstrong counties. Elections were held in 1988, 1991, 1994, 1997, and 2000 to annex the remaining portions of the District within the present boundaries.The PGWCD project has access to cloud systems moving out of Oklahoma into its target area, which currently consists of nearly 4.1 million acres in the eastern sector of the Texas Panhandle. The staff of the PGWCD can provide additional information about this project (806) 883-2501; Flight Tracks | Panhandle Groundwater.
Trans Pecos Weather Modification Association (TPWMA)
Cloud-seeding has been underway west of the Pecos River since May 2003. The TPWMA consists of the Ward County Irrigation District and other political subdivisions within Culberson, Loving, Pecos, Reeves, and Ward counties. Its target area in that part of Texas along and west of the Pecos River consists of 5.1 million acres. TPWMA aircraft are based at the airport in Pecos, Fort Stockton, or in Alpine. Additional information is available about this project through the Ward County Irrigation District in Barstow (432-445-6834). Latest data on operations can be found here: West Texas Weather Modification Association
Rolling Plains Water Enhancement Project
Eight counties are sponsoring cloud seeding in the Rolling Plains area from near Abilene north and eastward toward the Red River valley. Originally, in 2015, the counties constituted a “target area” of 3.5 million acres, and today additional counties have since been added to the west and southwest encompassing the counties of Knox, Baylor, Haskell, Scurry, Fisher, Jones, Mitchell and Nolan. The counties contract with a West Texas Weather Modification Association, - licensed and permitted by TDLR, for the cloud-seeding services. The seeding aircraft operate from within the multi-county target area. The seeding aircraft operate from within the multi-county target area. Information on their recent operations can be found here: Rolling Plains Water Enhancement Project
Each of the projects described above is permitted by TDLR, with each permit covering a period that can range up to four years in duration. The project sponsor, or contractor, is also required to keep current a Texas weather modification license, which is renewed annually.
Individuals or organizations with questions about cloud seeding but with an interest in doing so should email weather.modification@tdlr.texas.gov about any weather modification permitting and licensing matters, or for general information about cloud seeding technology.
