Southern Chile suffers frontal system with rain and hail, in spring
Written and reported by Macarena Bravo | Lee esta noticia en Español
The frontal system that affected central-southern Chile during the weekend of September 20 brought rain, hail, and strong winds that raised concerns within the fruit sector. Although rainfall was not uniform across all regions, it did have effects on crops at key stages of development, specifically flowering and fruit set.
A frontal system happens where two air masses with different temperatures and humidity levels meet. When a frontal system passes through an area, it often brings changes in temperature, wind, and precipitation, including rain, hail, or storms.
Víctor Catán, the president of the National Federation of Fruit Producers of Chile (Fedefruta), considers this a climate event considered normal for the season, but one that is not without risks.
He noted that precipitation varied across different areas, ranging from 5 to more than 70 millimeters, and urged producers to step up health monitoring and review management protocols.
He stressed the importance of acting quickly to prevent fungal diseases, especially in fruit trees currently in bloom or at the beginning of fruit set, such as stone fruits. “You have to check and recheck,” emphasized the industry leader, who also addressed the need to assess thinning and strengthen orchard nutrition after the frontal system passed.
Marlene Ayala, professor at the Pontifical Catholic University of Chile and researcher in plant physiology, said to FreshFruitPortal.com that “the rains rain and hail, though very localized. In some areas, such as Ñuble, the impact was greater.”
According to Ayala, the biggest problem arises in fruit trees in full bloom or early fruit set, such as nectarines, cherries, and some pear varieties.
She added that moisture on flowers hinders pollination, especially if pollen gets wet or if bees cannot work due to weather conditions. “This can result in lower fruit set and, eventually, reduced yields,” she explained.
Ayala noted that the combination of moisture and spring temperatures creates favorable conditions for fungal and bacterial diseases. “It’s very likely that producers are now applying foliar products to prevent infections like botrytis or monilia,” she said. This situation not only raises health risks but also increases the costs of phytosanitary programs, impacting crop profitability.
In some areas where hail was recorded, there was direct physical damage to leaves, wood, and fruit. “Hail scars fruit, especially those already set. These damages are often irreparable and lead to discarding a significant portion of production,” she said, adding that in some cases damage could exceed 50% of fruit, especially if hail was intense.
The professor also referred to the impact that rains can have on soil temperature, a crucial factor in spring to activate roots and facilitate vegetative growth of the tree. “Rain can cool the soil and delay the transition from flowering to fruit growth, affecting the crop’s normal development,” she explained.
What to remember in the face of a frontal system
Regarding management measures, Ayala highlighted that crops with physical protection, such as plastic covers or roofs, benefited since these systems prevent direct moisture on flowers and fruit and can even cushion hail impact. However, she acknowledged that in Chile the use of hail nets is still uncommon, unlike in countries such as Argentina.
For post-event management, she recommended carefully assessing damage in the coming days. “Hail damages even when not immediately visible. Many producers may think there was no damage, but as days pass, the effects will become evident,” she warned.
With new rains forecast for Friday, September 26, Ayala urged the industry to strengthen preparedness for increasingly frequent and erratic climate events.
“This month has been especially tough: frosts, rains, hail, and waterspouts. It’s a wake-up call to implement more climate mitigation and protection measures, especially in such a key month for fruit trees,” she said.
Fedefruta’s president added that the new frontal system projected for this weekend is expected to be less severe and without frost risk, according to the latest information available to the association.
Finally, the expert warned about the uneven impact of these phenomena, especially on small farmers. “Many lack forecasting systems or protective infrastructure. These types of events leave them in a critical situation,” she concluded.
Earlier this month, agricultural climatologist Patricio González Colville of the University of Talca warned that September would be a transitional month between a cold, dry winter and an increasingly warm, arid period: “It’s a hinge month, when frontal systems, late frosts, and alternating cold and warm days can still occur. The recommendation is caution, especially since crops are flowering.”
He also noted that from October onward, hot days are expected to dominate, with extreme temperatures reaching between 25°C and 33°C, a trend already observed in past springs under La Niña conditions.
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