The Swiss hail network

Purpose of the Swiss Hail Network

The purpose of the Swiss Hail Network is to record for the first time the impact energy, grain size distribution and precise time of hailstorms thanks to new sensors, and in doing so create a data set for improving our understanding and the monitoring, measurement, warning, short-term forecasting and climatology of hailstorms in order to reduce hail damage in the long term.

This purpose is served by the combination of hail information from weather radar data, observations from the population, data on hail damage to vehicles and data from the automatic hail sensors, which is new and unique worldwide.

The measuring network

The Swiss Hail Network is a fully automatic measuring network consisting of 80 sensors that are being installed in the three regions of Switzerland with the highest probability of hailstorm occurrence. The aim is to record as many hail incidents as possible. The Hail Network will be operated over a period of eight years.

A research paper conducted by the Mobiliar Lab for Natural Risks and MeteoSwiss has, on the basis of radar data, confirmed that hail most frequently falls in the Napf Region, the Jura and Southern Ticino. The hail sensors are therefore being installed in these three regions: Twenty-five sensors will initially be installed in the Napf Region in spring 2018, with a further 15 to follow in this region, 25 in the Jura and 15 sensors in Southern Ticino by spring 2020.

The Swiss Hail Network is being financed by Swiss Mobiliar as part of its social responsibility with a sum of one million francs. Swiss Mobiliar is providing the data to the Mobiliar Lab for Natural Risks at the University of Bern and the Federal Office of Meteorology and Climatology MeteoSwiss free of charge.

The new data set will be incorporated into the ongoing hail research at the Mobiliar Lab for Natural Risks at the University of Bern and take science a big step forward.

The sensor

The “HailSens” hail sensor consists of a Makrolon disc with a diameter of 50 cm. The Makrolon disc begins to oscillate upon the impact of a hailstone. The oscillations are recorded by a highly sensitive microphone. This way the hail sensors measure the kinetic energy, the grain size and the time of impact. The data are transmitted in real time via the mobile network to a central storage location at MeteoSwiss.

The company inNET Monitoring AG from Altdorf has developed the hail sensor based on an idea of Prof. Martin Löffler-Mang from htw Saarbrücken and is responsible for constructing and maintaining the sensors.

Further information about the sensors can be found here.

Contribution of the population to hail research

The hail report function in the MeteoSwiss app where users can record their observations about hail has already been providing researchers with valuable inputs for three years. Over 53,000 of the reports entered to date are of major significance for the improvement of hail warnings. Thanks to the Hail Network, additional important parameters and data can be collected.