WTW is partnering with the Karlsruhe Institute of Technology and NASA to explore the ways in which the understanding and modelling of hail risk may be improved.

In the latest phase of its long-term collaboration with KIT, the risk advisory’s project will explore the challenges posed by hailstorms, with particular focus on the impacts of climate change.

Hailstorms rank among the costliest severe weather perils, particularly in Europe, where recent years have seen significant insured losses. As climate change modifies hail formation processes and adds complexity to this peril, understanding hailstorm characteristics, such as frequency, intensity, and spatial distribution, has become a top priority for re/insurers.

In the latest phase of the collaboration, the hail model will be improved through a refined and extended time series of overshooting cloud top detections from satellites by NASA, which serve as proxies for severe storms and hailstorms, as well as a new model setup for hail hazard assessment.

Researchers will also explore how climate factors influence hailstorm characteristics, including hailstone size, frequency, and damage potential.

“Hailstorms are a growing concern for the (re)insurance industry, particularly as climate change introduces new uncertainties around their behaviour,” said Dr Daniel Bannister, weather and climate risks research lead at WTW. “Our continued collaboration with KIT and NASA ensures we remain at the forefront of scientific research, enabling us to provide (re)insurers with the insights they need to respond to this complex peril.”

Benjamin Scarino, a research scientist at NASA’s Langley Research Center, added: “With state-of-the-art identification techniques we can quantify severe storm distribution and frequency with an exceptional level of consistency and persistence that’s only granted by satellite measurements. Long-term satellite data records allow us to provide the re/insurance industry, project partners, and the research community with valuable insights into severe storm activity and risk.”

This collaboration also builds on the original Willis European hail model, the first stochastic hail model to cover the whole of Europe. Since its introduction in 2014, the model has been widely adopted by re/insurers across the region.

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