Why are there hailstorms if it's not summer?

BarcelonaThe effects of the climate crisis are increasingly evident in our country, and this spring has been no exception, despite the end of the drought. The spring storms of April and May are producing exceptional hailstorms, unprecedented at this time of year since records began in Ponent or Terra Alta. These episodes have caused serious damage to crops and fruit trees in the area.

The largest hail sizes were recorded mainly on April 19 and 26 and May 4 and 5. In fact, according to Agroseguro's calculations, the storms on the weekend of April 19 alone affected nearly 10,000 hectares of fruit trees in Catalonia. In Ponent, hails of up to three centimeters were recorded, but in Arnes, in Terra Alta, they were almost four centimeters. Harvests in regions such as Segrià, Noguera, Urgell, Pla d'Urgell, and Segarra have fared the worst. Barcelona has also seen hailstorms this weekend, with hailstorms affecting Vallvidrera and Collserola.

The problem is that farmers are unprepared for such strong hailstorms in spring. "For the farmers, hail or stones in April can cause much more damage than a strong hailstorm in July," Carme Farnell, a technician with the forecasting and monitoring team of the Catalan Meteorological Service (SMC), told ARA. The expert emphasizes that the vegetative cycle of some fruit trees is "very sensitive" at this time of year. Furthermore, many crops that have "anti-stone" nets have not yet been installed.

Stones increasingly larger due to climate change

It's clear that the climate crisis is increasing extreme weather events. Air and sea temperatures are rising, and there's more water available in the atmosphere. "These elements make conditions more suitable for more intense hailstorms and hailstorms, which leave everything whiter," says Farnell.

However, the expert remains cautious: "To draw final conclusions about the impact of climate change on these types of events and future trends, we need to accumulate records for ten or twenty years." These are very irregular events that depend on many factors.

In this regard, Farnell emphasizes that years ago, silver iodide was used in Ponent to break up the most dangerous hailstorms, a practice that is now prohibited by law in Catalonia. Therefore, the seed data may not fully reflect the effects of the weather at the time. And now we must add that there is more data than before thanks to new technologies and social media. "We have a much more massive information base than before; the social impact of smartphonesallows us to experience more significant hailstorms than before. In Empordà, where hailstorms exceeded 10 cm in 2022, a size considered a giant hail and a record in Catalonia. "Unlike Ponent, all these towns have the characteristic of being close to the sea; marine humidity and increasingly higher temperatures are perfect conditions for generating larger or giant hailstorms in these areas, and this is a direct effect of climate change," explains Farnell.