Record breaking ECSS2025

  • 350 participants
  • 41 countries represented
  • 200 posters
  • 80 talks

We thank our local organizing partner, the KNMI – Royal Netherlands Meteorological Institute, EUMETSAT, and the European Meteorological Society for their support in making this conference possible.

Official ECSS2025 Conference Photo (photo credit: ESSL, Igor Laskowski)

Next to the record numbers, many participants have been very pleased about the outstanding scientific excellence presented at the conference by a highly dynamic and competitive research community.

Nikolai Dotzek Award to Yvette Richardson

The 𝗡𝗶𝗸𝗼𝗹𝗮𝗶 𝗗𝗼𝘁𝘇𝗲𝗸 𝗔𝘄𝗮𝗿𝗱, the most prestigious prize in the severe weather research community, is presented every second year in memory of ESSL’s founding father, Dr. Nikolai Dotzek, for an outstanding contribution to the science of severe storms.

This year, the Nikolai Dotzek Award went to Professor Yvette Richardson (Penn State University, US) for her outstanding contributions to understanding tornadogenesis and supercell dynamics and for her immeasurable impact on science through supervising students who have gone on to develop impressive research careers of their own.

Nikolai Dotzek Award Ceremony at the ECSS2025 Conference Dinner on 19 November 2025 in Utrecht, the Netherlands. From left to right: Alois Holzer, ESSL; Michou Baart de la Faille, ESSL; Yvette Richardson, Penn State University – Nikolai Dotzek Awardee 2025; Bogdan Antonescu, ESSL; Pieter Groenemeijer, ESSL. Photo: ESSL, Igor Laskowski.

Professor Richardson’s research encompasses the complete spectrum of severe convective storms. Her research integrates state-of-the-art numerical modeling with cutting-edge observational approaches to understand storm formation and evolution. Her modeling studies have systematically investigated how temporal and spatial variations in environmental parameters influence supercell strength, rotation, and longevity.

On the observational side, she has used mobile radars to capture the fine-scale structure of supercells, and working with Prof. Paul Markowski, pioneered pseudo-Lagrangian balloon-borne sensors that provide three-dimensional in-situ thermodynamic observations within supercells.

Her leadership in major field campaigns (e.g., VORTEX2) has fundamentally advanced understanding of the discriminators between tornadic and non-tornadic supercells, addressing one of the field’s most challenging forecasting problems. Beyond research, she co-authored the definitive textbook “Mesoscale Meteorology in Midlatitudes” (2010), now the standard reference for graduate education in this field worldwide.

For this accumulation of important achievements, it is ESSL’s pleasure to award Professor Richardson the 2025 Nikolai Dotzek Award.

MTG focus at ECSS2025

A full day of the European Conference on Severe Storms was dedicated to the new MTG satellites and related topics. EUMETSAT as a co-sponsor of the ECSS and the ESSL were happy to see the strong interest and ongoing user uptake of the novel data. A record number of ECSS participants is a clear sign of the importance of this topic.

EUMETSAT representatives and conference organizers at the ECSS2025 stage (from left to right: Alwin Haklander, KNMI; Rutger Boonstra, KNMI; Michou Baart de la Faille, KNMI and ESSL; Pieter Groenemeijer, ESSL; Stephan Bojinski, EUMETSAT; Natasa Strelec Mahovic, EUMETSAT; Tanja Renko, ESSL; Alois Holzer, ESSL). Photo: ESSL, Igor Laskowski.

On 21 November, a forecaster workshop on MTG is offered. 70 forecasters from all over Europe are registered for that event.

ECSS2025 Programme published

The scientific programme for the European Conference on Severe Storms was published on 8 August. Corresponding emails were sent to the contributing authors and co-authors.

The submissions promise a high-quality and diverse scientific programme. 220 posters and 82 oral presentations were selected by the Scientific Programme Committee (SPC) chaired by Dr Kelly Lombardo. In many cases, the decision was not easy. The ESSL would like to thank all members of the SPC for their important voluntary work.

In addition to the presentations, a panel discussion on the various improvements and knock-on effects for nowcasting expected from MTG is scheduled for late Tuesday afternoon during the conference week.

On Wednesday, a panel discussion will be held to assess the rich legacy of Dr Chuck Doswell who passed away earlier this year.

ECSS2025 Scientific Programme

Due to the slight delay in finalizing the programme, the deadline for the “Early Registration” fees has been postponed to 25 August at 12 UTC. More information on the registration process can be found here.

MTG LI at ESSL-EUMETSAT Forecaster Testbeds

Within the context of the cooperation between EUMETSAT and ESSL on user preparation for the MTG data, an experimental visualization of Lightning Imager (LI) data was introduced to the ESSL Weather Displayer. Its preliminary name is “Geometry and density” and it connects all the detected LI groups (connected pixel detections at one acquisition frame of 1 ms) within one single LI flash (collected LI groups that are correlated in space and time within 330 ms) and can be taken as a proxy for the geometry of the flash as seen from space. Each flash is given a different colour. Such a flash geometry can cover large areas, something that has earlier been discovered by using the ISS-LIS and GOES-GLM instruments. In the ESSL Weather Displayer, the visualization combines this information with data on highly active convective cells. Those active cores are made visible via plotting the LI group density if surpassing 1 LI groups per km² within a 5 minute time frame (colour shading from black via magenta, red, orange and yellow to white). Possible applications of such a product may range from public outreach activities via identification of new active updrafts all the way to lightning safety at airports.

LI group density is also visualized in gridded form. In addition, the area size of flashes is plotted for each single flash (the size of red or yellow circles related to the flash area). This allows a forecaster to identify physical processes that are ongoing within a convective complex. Large flash areas are typical for flashes in the stratiform regions while a high number of small flashes can be indicative for a very intense updraft, as it is often seen with supercells in early LI data.

You can read the full newsletter here.

Figures: Screenshots from ESSL Weather Displayer for a geographic area of Albania and surroundings on 4 October 2024 at 09:00 UTC. Left: LI Group Area (red circles). Middle: LI Group Density. Right: LI Geometry and Density (geometry approximation of LI flashes and LI group density above 1 for identification of active convective cores). Data source: EUMETSAT. Visualization: ESSL.

Press release: Europe needs “Twisters” campaign

Wiener Neustadt, Austria, 15.07.2024

Europe needs Twisters campaign

Researchers from all over Europe are organising high-density measurements of severe storms. Similar to the new film Twisters, the plan is for mobile storm chasing teams to collect essential weather data directly from storms.

This is planned to be ground-breaking. Severe weather researchers from 14 European countries want to work together to get to the bottom of severe thunderstorms so that they can provide better warnings in future. To this aim, they are currently planning the largest European measurement campaign on severe thunderstorms to date. “We want to use the latest technologies, such as weather drones. To do this, it is extremely important that mobile measurement teams get very close to the storms. This is the only way to gather the crucial information,” says Alois Holzer, initiator of the European “TIM” measurement campaign to start in 2026.

As can be seen in the new movie Twisters, the European research teams will also be tackling the storms with the newest generation of weather sensors. “In contrast to some scenes in the entertainment film Twisters, however, the highest safety standards apply in our research campaign, and we have also made a joint commitment to responsible behaviour with regard to the environment and the local population,” emphasises Alois Holzer, Director of Operations of the European Severe Storms Laboratory ESSL in Wiener Neustadt.

While the basic scientific structure is to be financed through traditional research funding, the project is still looking for major donors for the individual mobile measurement teams. Alois Holzer says with a twinkle in his eye: “We hope that the kind of support from major donors possible in North America can also be achieved in Europe. We are also in dialogue with various public authorities.”

The urgency of being able to better understand and predict severe weather, and thus to strengthen civil defence, is certainly given, as the frequent severe weather events show. The measurement campaign will focus on hailstorms, flash flood events, dangerous squalls and tornadoes. In the past year alone, severe thunderstorms have caused 524 fatalities in Europe, as reported by the ESSL.

The ESSL is an independent, non-profit research institute based in Wiener Neustadt in Lower Austria. It also operates the European Severe Weather Database (ESWD) and is a European leader in the training of meteorologists in the field of severe weather warnings. A year ago, the ESSL established the International Fujita Scale (IF-Scale) as a new standard for categorising tornado damage.

This press release is under embargo for re-publishing until: Wednesday, 17 July 2024, 00:00 UTC

LINKS:

European Severe Storms Laboratory (ESSL):         www.essl.org
TIM Field Campaign:                                                  www.tim-campaign.eu

LIVE EXPERT TALK:

The TWISTERS expert talk will take place on Tuesday, 16 July 2024:

English Expert Talk 11:30 CEST Vienna, Rome, Berlin, Paris, Madrid 10:30 WEST London, Lisbon
German Expert Talk 12:00 CEST Vienna, Rome, Berlin, Paris, Madrid 11:00 WEST London, Lisbon

Attendance:

On-site participation: ESSL Research and Training Centre
Bräunlichgasse 6a
A-2700 Wiener Neustadt, Austria
Registration required via: tim@essl.org
Online Participation: Microsoft Teams live event Registration via:
Microsoft Teams Event

Hail record broken again – 19cm hailstone confirmed in Italy

Less than a week after setting a new European record, a hailstone 19 cm in diameter was found in Azzano Decimo, Italy.

Record breaking hailstone in Italy
 © Tornado in Italia – Marilena Tonin

The previous record of 16cm in Carmignano di Brenta from 19 July lasted for only five days. On 24 July 2023 at about 11 PM in the evening, giant hail hit the town of Azzano Decimo, where the record breaking hailstone was found. After a thourough examination of the reports and photos, the specialists of the European Severe Weather Database (ESWD) came to the conclusion, that the diamter of this hailstone can be confirmed as 19 cm.

The new hailstone comes very close to the world record of a hailstone from 23 July 2010 in Vivian, South Dakota, with a diameter of 8 inches (20.3 cm).

The high frequence of hail in Northern Italy is consistent with research results of the European Severe Storms Laboratory (ESSL), showing, that this region has experienced the largest increase in the frequency of large hail, compared to other European regions in the past decades.

200% increase of large hail in Northern Italy since the 1950s
© ESSL / Francesco Battaglioli
Increase of hail events in Europe
© ESSL / Francesco Battaglioli

At the end, ESSL want to thank its local partners, as PreTemp in Italy, and the reporters of hail to their great collaboration and contributions to the European Severe Weather Database (ESWD)!

New European record: 16cm hailstone found in Italy

On 19 July, severe hailstorms affected large parts of Southern Europe. According to the experts of the European Severe Storms Laboratory (ESSL) so-called “giant hail” (hailstones with a diameter of more than 10 cm) was reported 24 times; 2 times in Croatia and 22 times in Italy!

Record breaking hailstone found in Carmignano di Brenta (Italy)
© Tornado in Italia – Floriana

In Croatia, the largest hailstone was found in Ribnik, estimated to be 13 cm in diameter. In Italy, the largest hailstone fell in Carmignano di Brenta. The specialists of the European Severe Weather Database (ESWD) estimate the size of this hailstone to be 16 cm in diameter, based on photos.

“According to our information, this would be the largest recorded hailstone in Europe”, says Thilo Kühne, Quality Control Manager of the European Severe Weather Database. “The previous record was a 15 cm hailstone from 20 June 2016 in Sânandrei, Romania”.

Besides enormous economic damage, the hail caused 109 injuries on that day alone, according to the European Severe Weather Database.

Hail reports 20 July 2023
© ESSL / ESWD

ESSL obtaining its data from a large European network of weather entusthiasts and cooperating weather services. The Italian cases, including the new record braking hailstone, were reported by PreTemp, which collaborates closely with ESSL.

The experts of ESSL and the European Severe Weather Database urge all people sending photos to the weather services or our data base, or posting hail pictures on social media, to use a ruler, coin or other reference objects next to the hailstones when making a picture. This makes it easier to estimate the exact size of hailstones.

ESSL supports civil defense exercise

ESSL was asked by the City of Wiener Neustadt to support a major civil defense exercise for the city and surrounding districts. On July 5th, shortly before the start of the exercise, ESSL Director of Operations Alois Holzer gave a lecture on tornado basics as a prelude for the management team of around 40 officials. The tornado scenario of the exercise concerns urban areas.

Kick-off presentation at civil defense exercise for City of Wiener Neustadt and surroundings on 5 July 2023

Already 10 years ago, ESSL provided the tornado scenario for a similar civil defense exercise. The recent talk gave the participating entities insight into the impacts of violent tornadoes. Part of the presentation was the case of 24 June 2021 over Czechia, when 6 persons died and hundreds were injured in an F4 tornado. Even more people were killed in the historical tornado event of the year 1916, when 34 persons died in another F4 tornado that struck the northern neighborhoods of Wiener Neustadt.

From left to right: Markus Biffl (Head of City Administration Wiener Neustadt), Alois M. Holzer (ESSL Director of Operations), Doris Hailzl (Head civil protection department and main organizer of exercise). Background: situation room for civil defense emergencies.

ESSL welcomes Météo-France as a new Full Institutional Member

In June 2023, Méteo-France has become a member of the European Severe Storms Laboratory. This means that they have joined the present 25 Institutional Members of ESSL: public or non-profit organizations in Europe active in the realm of weather and climate forecasting or related fields. The ESSL Team extends a warm welcome to Météo-France, which will now have full access to the European Severe Weather Database to support its activities. In addition, full ESSL members have a vote in ESSL’s General Assembly and benefit from reduced participation rates in ESSL activities. ESSL is looking forward to the cooperation with Météo-France.