Even today, in Italy and in the world, some farmers rely on the so -called “Anti-Grandine” cannonstools that generate with small explosive charges shock waves and smoke Towards the sky and which, according to a widespread theory in the late 19th century, should influence the rainfall preventing the formation of hail and preserving the crops. Even if some theories on their operation may seem sensible, the reality of the facts is that There is no substantial and solid evidence of their effectiveness. Traditions and customs, however, are hard to die, especially in areas such as theagriculturewhere innovation often lives with knowledge handed down over the centuries. The farmer I owe in fact defend the fruit of one’s work from climate change and from uncontrollable weather eventslike the harmful summer hailstorms: impotence in the face of nature can push to cling to theories denied for centuries.
When the “anti-Grandine” cannons were born: history
The history of the anti -lecture cannons starts from very far: since 14th century There are evidence of the use of cannon in the hope that the sound would influence the formation of clouds and, already In 1750, The Empress of Austria prohibited the use of cannons in the countryside, for Avoid fatal accidents And for the fear that the influence on disadvantaged rainfall other surrounding areas.
In 1896 M. Albert StigerBorgomastro di Windisch-Fistritz in Austria, began to experience the use of cannons in his possessions. The theory on their functioning, also widespread in Italian academic environments, was in the hypothesis that the particles of dust and smoking they would have absorbed the humidity of the air, Forming nuclei, around which the drops of water would have joined and then falls back to the ground like rain, thus subtracting energy and raw material from the clouds. A principle Not too bizarre, similar to that of the modern Cloud Seedingbut applied to violent temporal systems and with a disbursement from the ground.
Stiger cannons, in the shape of a megaphone and aimed directly towards the sky, produced a visible cloud capable of reaching too 300 meters high. In 1896, the first year of study with 6 cannons, The area did not record hailstorms, result replicated in 1897 When The cannons in the village reached 30 arranged according to precise grills, while surrounding regions were instead affected by hail.
The success of the experiments spread in central-southern Europe, especially in the wine areas of ItalyFrance, Germany and Austria: Dr. E. Ottaviri in 1898 brought cannons to Italy, and in 1900 they already recorded it 10,000 active.
The following years were however poor in satisfactions: the Italian deputy eighth (initially skeptical, but then convinced by the first experiments) in a report from 1903, admitted that The damage from hailstorm In the areas covered by cannons over the years they were however hugedespite their preventive and continued use. Already in 1906 The cannons were almost entirely abandonedalso because of fatal accidentsas in 1903 where 5 deaths and 30 serious events were only in Lombardy. Intense temporal seasons throughout Europe highlighted the uselessness of these tools even more.
The first return: the 1950s
The cannons had a second golden period in the 1950s, starting from the United States but also in Italy and France, where they spread above all rockets to explode at altitude. Curiously, the theory behind their operation took steps back, returning to the medieval concept of sound, or rather of theshock waveas a means of destroying hail beans.
The idea, already discarded by the studies of the Austrian scientist Pernter in 1900, was further discredited by subsequent American experiments, carried out in the general enthusiasm in the 1960s. These showed that the cannons could not to destroy hail beans over 1 meter away and which also using 1 kg of Tnt (Trinitrotilane, an explosive) You could damage only within 15 meters from the explosion. Moreover, the hail falls (above all) during intense temporal temporals with frequent lightning and thunder, even stronger boots than a cannion and generated at altitude.
Whatever the theories at the base were, cannons and rockets were sold in Italy until the early 70s, before one law prevented the sale of the latter.
Yet another return: the cannons in the third millennium
It seems absurd, but the anti -hail cannons are returned in vogue also in the third millenniumas reported by World Mereteological Organization In 2001. A “in favor” study of the cannons, in 2023, highlighted one variation of humidity in the air above an anti-GRANDINE cannon Even up to 40 minutes after a sequence of explosions. Also admitted that the variation was not completely random (even the previous measurements the “cannonate” showed variations), the measurements were made at a maximum altitude 160 meters: the temporal clouds have altitudes of at least 1500-1800 meters and develop up to 10 km of altitudea scale very different from that of the study.
Nonetheless, the cannons are still sold, and also a dear price: an article by Stands Indian celebrates the production of cannons designed by the Indian Institute of Technology Bombay, at the cost of only “15-20 lakh” rupees or 17-22 thousand euros (For the Indian numerical system, a lakh indicates one hundred thousand units). The Giornale di Vicenza instead reported, in 2018, the installation of new plants in Italy at a price of about 37,000 euros.
The institutions at the moment still tolerate the use of this tool, despite the lack of scientific evidence: Conditions are placed in the shot frequency and in the distance from homes or other buildings, to avoid damage to infrastructure. A resolution of the Municipality of Guarene (CN) limits to 200 meters from homes and 50 meters from roads Public the installation of new systems, which cannot be used for more than 6 “cannoning” per hour. They are also needed Specific clearance to be requested from Local Aeroclubs and limitations in positioning compared to Airports and Eliporti.
