Does a Hail Cannon Really Stop the Hail?

CUAUHTÉMOC, MEXICO — Since the early 1980s, farmer Carlos Pérez has relied on a hail cannon to protect the apple orchards that have been in his family for three generations.

Perched on a corrugated metal outhouse, Pérez’s hail cannon is a 3-meter (10-foot) device that resembles a metal funnel. When turned on, it emits explosive booms, blasting shock waves into the atmosphere. The device is designed to disrupt the formation of potentially damaging hailstones before and during storms.

For decades, farmers and fruit growers like Pérez have depended on these devices to preserve their crops, despite a lack of scientific evidence that they work. Environmental campaigners argue that there’s a link between the use of these cannons and a reduction in rainfall, also without significant proof. Local and state governments are reluctant to decide if they should be permitted, leaving many farmers unsure as to whether they can use them.

In 2019, the municipal president of Cuauhtémoc, the local governing body, told Pérez that he couldn’t use his hail cannon until he could present a study on the environmental impact at his own expense, something the 65-year-old orchard owner is unwilling to fund each time he wants to use the machine. Three years later, officials in Cuauhtémoc still require hail cannon users to shut down their machines and fund their own studies. With his hail cannon out of action, Pérez says, his orchards are at risk.

He recalls one of the instances when his hail cannon “worked perfectly.”

“I was very worried because the hail was so strong,” he says, adding that he rushed out to turn on the cannon and witnessed the hail stones “disappearing” as they approached the perimeter of the cannon, instead falling “like snow.”

Farmers have been putting weather control methods to the test for hundreds of years to keep their livelihoods intact. Hail cannons have continued to evolve, despite some authorities’ unwillingness to take a firm stance on the machines.

One hailstorm has the potential to damage thousands of hectares of crops. In July 2019, more than 5,000 hectares (19 square miles) of crops were damaged after a hailstorm hit Zapotlán del Rey, Jalisco, in west central Mexico, with 2,500 hectares (10 square miles) deemed a complete loss for farmers.

Pérez, who lives in the northwestern state of Chihuahua, where the risk of hailstorms varies, now needs to rely on hail netting, a material web that provides a protective layer over his crops. It’s an added cost and frustration while his hail cannon sits idle.

The unpredictability of devastating weather is a constant fear for all farmers, but these devices can be an extreme and expensive solution. Pérez says his grandfather bought the hail cannon in 1983 from Germany. Pérez doesn’t recall how much it cost, but a manufacturer in New Zealand, which supplies the devices to farms and businesses around the world, sells them for around $40,000.

Graphic by Matt Haney, GPJ

Exactly how many people have these cannons is unknown. Marcial Reyes Cázarez, permanent consultant for the Ministry of the Environment, Climate Change and Territorial Development in western Mexico’s Michoacán state, says it has 1,200 such devices.

Dating back over 100 years and thought to have been first used by French farmers to protect their vineyards, hail cannons reemerged in the latter part of the 1990s, despite there being no “scientific basis nor a credible hypothesis to support” them, according to a report by the World Meteorological Organization in 2001. The same year, the Commission of Rural Development, under the Chihuahua state legislature, determined there wasn’t enough scientific evidence to prohibit or restrict the use of hail cannons. More than two decades after this report, many governing bodies across Mexico, including Pérez’s municipality of Cuauhtémoc, still haven’t decided whether to permit hail cannons.

Irma de la Peña, Cuauhtémoc’s head of ecology, says she has analyzed the arguments for and against and is unable to take a position, admitting that both sides lack scientific evidence.

“Everyone has said the same thing: There are no studies that prove anything … no scientific studies anywhere,” de la Peña says.

LILETTE A. CONTRERAS, GPJ MEXICO

Carlos Pérez’s son, Carlos Pérez Hernández, turns on the hail cannon, which sits in his father’s apple orchard near Cuauhtémoc, Mexico.

In 2017, however, Reyes Cázarez used a rain measuring tool called a pluviometer and a sound level meter, which measures the intensity of rainfall, to demonstrate that there was a relationship between the hail cannon explosions, caused by a combination of gases, and a reduction in the volume of rainfall.

The potential link between the cannon’s use and less rainfall is exacerbated by an intense and widespread drought across nearly 85% of Mexico, according to the NASA Earth Observatory, run by the United States government, with recovery hampered by a drier than normal January this year.

The Colectivo Ambiental Diente de León, an environmental rights campaign group founded by residents of San Salvador el Seco, in Puebla, an area with one of the highest threats of hailstorms, was so concerned with the possible link between the use of these cannons and a reduction in rainfall, members sent an official complaint to the Ministry of the Environment, Sustainable Development and Land Management of Puebla state.

Hail cannons are already banned in that state, as well as the western states of Michoacán and Colima, but the collective claims they are still being used in Puebla, despite the ban.

LILETTE A. CONTRERAS, GPJ MEXICO

Orchard owner Carlos Pérez says he has to rely on hail netting after the governing body of Cuauhtémoc told him he couldn’t use his hail cannon.

Collective member Gerardo Romero Bartolo says that following their complaint, two officials from the environment department visited the areas where the collective said hail cannons were put to use. They detected no hail cannon use, something the collective blames on the inspection being carried out in the fall, when hailstorms are unlikely.

The Ministry of the Environment, Sustainable Development and Land Management of the State of Puebla didn’t respond to requests for comment.

Three years after he was forced to stop the use of his almost 40-year-old hail cannon, Pérez vows not to give up his fight to use the device he and his family have relied on for decades.