A Cloud-Seeding Startup Is Not to Blame for the Texas Flooding

In the wake of a disaster, people often seek to understand the causes. The recent floods in Texas have sparked such debates.

Several factors may explain the substantial death toll from the swiftly rising waters, with some attributing the cause to a technique known as cloud seeding. They allege that a cloud-seeding firm called Rainmaker was responsible for amplifying the storm’s rainfall. However, the evidence does not substantiate these claims.

While Rainmaker operated in the vicinity days before the storm, Katja Friedrich, an atmospheric scientist at the University of Colorado Boulder, stated that “cloud seeding had nothing to do” with the floods.

Bob Rauber, a professor of atmospheric sciences at the University of Illinois, reiterated this view, labeling it a “complete conspiracy theory.” He stressed that people are merely searching for someone to hold accountable.

Cloud seeding is not a recent development; it has been practiced since the 1950s, according to Rauber. This method involves dispersing tiny particles, primarily silver iodide, into clouds.

Silver iodide mimics the structure of ice crystals, which encourages super-cooled water droplets to freeze upon contact. Rauber explained that this freezing is essential, as larger ice crystals can grow faster than super-cooled droplets, increasing the likelihood of attracting enough water vapor to eventually precipitate. If they remain super-cooled, there is a significant chance they will evaporate.

Only clouds with sufficient super-cooled water are suitable for cloud seeding.

In the U.S., cloud seeding primarily occurs during winter in the mountainous regions of the West. Here, mountains force air upward, leading to cooling and condensation of water vapor. Proper seeding can result in snow, which accumulates into a natural reservoir that replenishes artificial reservoirs during spring melt.

Despite decades of cloud seeding, its impact on precipitation has only recently become a research focus. “We have only recently developed the technology to assess it effectively,” Rauber stated.

In early 2017, Friedrich, Rauber, and their team conducted one of the most detailed studies on cloud seeding in Idaho. Over three sessions, they seeded clouds for a total of two hours and ten minutes, yielding about 186 million gallons of extra precipitation.

While this may seem substantial, it is insignificant compared to a major storm. “In the context of that enormous storm that caused the flooding in Texas, we’re talking about the atmosphere managing trillions of gallons of water,” Rauber remarked.

If Rainmaker had any minor influence, it would be negligible—essentially a rounding error. In reality, it had no effect.

To start, the company had seeded nearby clouds days prior to the storm. “The air over that area two days before was probably already drifting over Canada by the time the storm hit,” Rauber clarified.

Additionally, it is uncertain how effective cloud seeding is for the cumulus clouds commonly seen in Texas summers. These differ from the orographic clouds found near mountains and do not respond to seeding in the same way. Typically, they are short-lived and yield limited rainfall.

While cloud seeders attempt to enhance these clouds, Rauber noted that “the amount of rain from those seeded clouds is minimal.”

For clouds that last long enough, like thunderstorms, natural processes work effectively. “These clouds are highly efficient, and seeding them won’t make much difference,” he concluded.