UK scientists report changing risks of damaging hailstorms in a warming Europe

By the Climate Centre

Climate change may lead to less frequent but bigger and more devastating hail storms, new research by British scientists published in Nature Communications has shown.

“Hail is among the costliest of local hazards stemming from thunderstorms, yet despite this, there remain uncertainties about how it forms,” according to the scientists, from the UK Met Office and the Universities of Bristol and Newcastle.  

But recent improvements in modelling and computing “provide an opportunity to assess future hail threat at a continental-scale.”

The researchers attribute the decrease in the number of hailstorms to several factors: hail forms higher in the atmosphere as it warms, giving it more time to melt before reaching the ground, while “weakening large-scale circulation, affecting the vertical profile of winds [leads] to environments not beneficial for thunderstorm organization.”

Conversely, global warming could produce a “thunderstorm type similar to hail-producing storms found in the tropics, where the largest hailstones can still reach the surface. The findings suggest that, in the future, these storms will become most frequent over southern Europe, leading to regional increases in severe hail frequency.”

‘Future storms in the Mediterranean could bring giant hail and devastating impacts’

Study author Lizzie Kendon, Head of Climate Projections at the Met Office, said Friday: “These results … imply we need to be prepared for tropical-type hailstorms impacting Europe in the future, associated with very large hailstones that can cause severe impacts.”

Another author, Hayley Fowler, Professor of Climate Change Impacts at Newcastle University, added: “As a society we need to be better prepared for unprecedented extreme events and this study shows that future storms in the Mediterranean could bring giant hail, with devastating impacts.

“Recent hailstorms have caused significant direct damage to properties and infrastructure, crops, and even aircraft.”

The authors acknowledge “considerable uncertainty regarding the effect of enhanced melting associated with higher freezing levels on the largest hailstones,” and call for further studies of the potential for very large and damaging hail at the surface.

Freak summer hailstorms caused tens of millions of euros of damage in German villages near the southern city of Stuttgart in 2013, with “hailstones the size of tennis balls” raining down from the cloudy skies. It was captured by a local film-maker and meteorologist Marco Kaschuba, who measured the biggest hailstones at just over 14cm. (File image courtesy of Marco Kaschuba)