Man has been trying to influence the weather ever since he started growing crops. The methods to control the weather initially meant offering prayers and sacrifices to the weather gods and performing ritualistic dances. These went on for ages and are still practiced to this day in certain areas. It was at the very end of the 19th century when other measures were taken to control the weather and it involved the testing of a device called the hail cannon.
The hail cannon is a funnel-shaped device that allegedly disrupts the formation of hailstones by creating shockwaves. A mixture of acetylene and oxygen is burned in the lower chamber and the resulting blast passes through the neck and into the cone. There a shockwave s developed that travels at the speed of sound through the cloud formations above.
The device is fired repeatedly at 4-second intervals whenever a storm is approaching and till the time it has passed through. Normally what would have fallen as hailstones falls down as slush or rain. These were initially used in Italy where specially made cannons filled with gunpowder were fired at the clouds. Today, Mike Eggers Ltd, a New Zealand based manufacturer is the principal supplier of hail cannons in the United States. These machines sell for as much as $50,000 a unit and provide coverage over a radius of one-third of a mile.
There has been an ongoing debate about their effectiveness. The scientists who use them claim that they work. Scientists, on the other hand, are not convinced. They say that the thunder creates shockwaves which are much more powerful than the ones created by the hail cannon and if they don’t disturb the growth of hailstones, how can this?
Meteorologist Steve Johnson explained to Fox News, that the only way to suppress hail is by ice nucleation. “If you inject a tremendous number of embryos into the birth area of the thunderstorm, then it competes for the same water — and you’ll have more beneficial rain falling than a few large hailstorms,” he explained.
The first hail cannon was tested in 1896 based on the idea floated by an Italian professor of mineralogy in 1880 that the formation of hailstorm could be prevented by injecting smoke particles by means of cannons fired at thunderstorms.
The testing was performed in Austria by M. Albert Stinger, the Burgomaster of Windisch-Feistritz, and a famous winegrower. Stinger built a vertical pointing muzzle-loading mortar, resembling an upright megaphone about 2 meters tall. When fired, the mortar produced large smoke rings that rose to 300 meters.
Stinger built and tested several of these cannons and observed no hail for two years. The news spread across Europe and by the year 1899, there were 2,000 hail cannons operating in Italy alone. This number grew to 10,000 at the end of 1900. These canons were considered a success and when they failed, it was blamed on improper usage.
However, many hail cannon protected crops were lost during major outbreaks of damaging hailstorms that occurred during 1902-1904 and seeds of doubt were sowed into the peoples’ hearts about the cannons and they were mostly abandoned by 1905.
Hail suppression efforts pretty much ended in in Europe but they were reawakened in the late 1940s and 1950s in the United States and hail cannons somehow made their way back into the game. Now they are used beyond agriculture. Nissan, the U.S. based car manufacturer, employs hail cannons at their Mississippi factory to protect their brand new vehicles parked in the factory’s shipping yard.
Even though Nissan insists that these cannons work, scientists believe just the opposite but it is hard to prove due to the unpredictability of the weather.