Non è vero che non ha mai piovuto di notte

The claim that there has never been hail at night is incorrect, according to recent reports. The damage caused by reduced agricultural production due to hailstorms was estimated at over 44 million euros in 2023. A Facebook user posted on June 10 that "there has never been hail at night," adding that "weather has been artificially created for some time." According to the Agency for Environment (Arso), tracking the occurrence of hail based on the time of the event is practically impossible. They explained that hail typically occurs in the afternoon, but can also appear in the evening or at night during strong thunderstorm systems. Klemen Bergant, former director of the State Meteorological, Hydrological and Oceanographic Agency and current director of the European Meteorological Network (Eumetnet), presented a historical review of hail suppression methods in a professional article published in the journal Ujma in 2011. He explained that the method of hail suppression is based on the assumption that introducing additional ice nuclei into thunderclouds increases the number of hailstones while simultaneously reducing their average size. Smaller hailstones cause less damage and melt more easily during descent. This theory was proposed by American scientist Bernard Vonnegut in 1947. His findings suggested that silver iodide could serve as an effective condensation nucleus for the formation of ice crystals, as its structure is very similar to that of ice crystals. If silver iodide is introduced into areas with supercooled water droplets or high humidity, water would quickly freeze onto the silver iodide, resulting in numerous ice crystals. Experiments conducted by the National Center for Atmospheric Research (NCAR) in the 1970s showed statistically unpredictable results, as calculated total hail mass could either drastically decrease or multiply several times. Later extensive research in Switzerland confirmed that positive effects were absent, noting no significant differences between ordinary thunderclouds and those treated with silver iodide, with data even suggesting that treated clouds might have resulted in faster hailstone fall speeds and larger affected areas. In Slovenia, the experimental seeding of hail-bearing clouds with silver iodide began in 1999 and is carried out by the Maribor Airfield Centre. Bergant expressed skepticism towards hail suppression in his article, stating that the key issue with hail suppression is that despite scientific progress, our understanding of thunderstorms is not yet sufficient to reliably predict the effects of introducing additional ice nuclei into thunderclouds. He added that expanding aerial hail suppression to cover all of Slovenia is not justified until there is conclusive evidence that such suppression is truly effective. Arso explained last week to Razkrinkavanje.si that cloud seeding with silver iodide is not supported by the agency due to lack of proven effectiveness and ecological concerns. They noted that the term "seeding" is often used by proponents of the conspiracy theory regarding "chemtrails" or chemical trails from aircraft. According to data available on the Arso Meteo website, supporters of this theory claim that chemical substances are intentionally added to aircraft trails with unclear purposes affecting the weather. However, the meteorological scientific community unanimously agrees that these are simply typical condensation trails formed by mixing hot exhaust gases from aircraft engines with cold air at high altitudes. This physical phenomenon has been observed since the beginning of commercial aviation at high altitudes. Gregor Skok from the Department of Meteorology at the University of Ljubljana's Faculty of Mathematics and Physics explained in an article about the impact of condensation trails on the weather that these trails have no significant effect on short-term weather phenomena such as thunderstorms. Just like clouds, aircraft contrails can influence the atmosphere.