Hail causes growing losses worldwide

In the late afternoon and early evening hours of 23 July 2010, a supercell thunderstorm swept across South Dakota, unleashing barrages of extremely large hail, destructive winds, and a brief tornado. A resident later discovered a hailstone that still had a diameter of 20 centimetres and a weight of 880 grammes by the time the National Weather Service was able to measure it. An even heavier hailstone was recorded in Bangladesh on 14 April 1986 during a storm that killed 95 people – according to the World Meteorological Organisation, that chunk of ice weighed more than 1 kilogramme.

While huge hailstones like these are relatively rare, destructive hailstorms are not. In 2023, severe convective storms (SCS) led to insured losses of $71 billion worldwide, according to Gallagher Re's Natural Catastrophe and Climate Report. "Hail continued to be a dominant driver of loss costs," Gallagher emphasises. It "typically accounts for 50 to 80 per cent of SCS claims in any given year." 

And in this case, the trend is nobody's friend: Insured SCS losses in the US have shown a 9.6 per cent annual rate of growth since the year 2000, while Europe has also seen a striking increase in severe weather events over the last years. Almost 10,000 large hail events were reported in the EU for 2023, making it the third record-breaking hail season in a row. 

According to the European Severe Storms Laboratory (ESSL), France topped the list of large hail reports at more than 1,500, but "in terms of the most damaging hailstorms, Italy took the commanding lead," the ESSL says.

Understanding regional risks is the first step towards minimising damage. Businesses in northern Italy or Colorado, for example, may have a greater need to invest in hail protection than those in Florida, where the ice often melts before reaching the ground. Valuable insights are available from institutions such as the ESSL in Europe, the National Oceanic and Atmospheric Administration (NOAA) in the US, and Canada's Northern Hail Project. These organisations are researching the geographical distribution of risks as well as the factors that enable more precise forecasts. 

The private company Arturo Intelligence addresses similar challenges using aerial imagery and artificial intelligence. Marty Smuin, CEO of Arturo, emphasises "the urgent need for predictive data- and science-based measures to mitigate risks." As climate change continues to impact the frequency and severity of these events, he stresses that "stakeholders must collaborate to protect properties and communities."

Primarily a summertime phenomenon, hail often destroys crops but also damages buildings, cars, and planes. Choosing robust roofing materials is essential – modern, high-quality composites and metal tend to outperform the widely used asphalt shingles, according to Ian Giammanco from the US Insurance Institute for Business & Home Safety (IBHS) Research Center. Air conditioning systems and solar panels are also vulnerable, as they are usually not designed to withstand large hailstones. Glass surfaces such as skylights, car windows, and greenhouses are even more at risk.  

The IBHS offers a free disaster readiness guide to help businesses minimise the risks associated with thunderstorms, including hail damage. Effective planning starts with assessing the company's exposure and developing a business continuity plan. The institute emphasises the importance of preventative maintenance measures on buildings and commercial doors to avoid or reduce losses. 

Additional measures may be necessary to upgrade and fortify buildings against severe weather. In hail-prone areas, IBHS recommends strengthening roofs, installing impact-rated windows and doors, adding protective screens over HVAC units, and using impact-rated cladding systems. Many modern buildings require these upgrades even more urgently than old ones because their materials were optimised for cost-effectiveness, low weight, and other factors compromising robustness. However, diligent maintenance is essential in any case, as older structures and materials may become brittle and fragile.

The IBHS also provides a checklist for businesses that were damaged by a major storm. Their goal should be to "build back stronger," the institute says. However, once a severe weather event has struck an area, demand for competent contractors will be high. Preparing before a storm is on the horizon can help avoid delays and ensure that necessary improvements are made in time.