Modern building façades are especially prone to losses in severe hail events because hailstones frequently strike at an oblique angle due to wind action. This is true, for example, for building exteriors in Germany equipped with modern thermal insulation systems. With such insulated façades, the thin plaster finish is often chipped off by hail and the building is then damaged by wetness. The more complex and costly façades on modern office buildings can also produce major individual losses.
In Switzerland, where building standards are similar to those in Germany, the proportion of damaged buildings was systematically higher for more modern structures than for older ones: For example, in the canton of Aargau roughly 8% of buildings from the 1940s suffered damage in hailstorms, whereas the figure for buildings constructed after 2000 was 15%.
A look at Switzerland also shows how resistance to hail can be improved. The Swiss Hail Register (www.hagelregister.ch) was introduced in 2010 in cooperation with homeowner and insurance associations and the Swiss Society of Engineers and Architects. The initiative motivates manufacturers of construction materials and components to have their products tested and certified for hail resistance. The result is a central database with a certification mark for hail-resistant construction. An offshoot of this initiative is also operating in Austria.
For other countries, including Germany, an initiative of this kind to limit future losses would be highly desirable – not least because of the anticipated consequences of climate change.
* Rädler, A.T., Groenemeijer, P., Faust, E., Sausen, R., 2018: Detecting severe weather trends using an Additive Regressive Convective Hazard Model (ARCHaMo). J. Appl. Meteor. Climatol., DOI:10.1175/JAMC-D-17-0132.1
** Sander, J., Eichner, J.F., Faust, E., Steuer, M., 2013: Rising Variability in Thunderstorm-Related U.S. Losses as a Reflection of Changes in Large-Scale Thunderstorm Forcing. Weather. Clim. Soc., 5, 317–331, DOI:10.1175/WCAS-D-12-00023.1.