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.

Mayor of Wiener Neustadt and Lower Austria Science Officer Visit ESSL

On the occasion of the first EUMETSAT-ESSL Testbed in 2023, the mayor of the city of Wiener Neustadt, Klaus Schneeberger, and the head of the governmental science department of the Federal State of Lower Austria, Martina Höllbacher, paid a visit to ESSL this week.

From left to right: Alois M. Holzer (Director of Operations, ESSL); Martina Höllbacher (Head of Science, Federal State of Lower Austria); Klaus Schneeberger (Mayor, City of Wiener Neustadt)

ESSL staff informed the officials on the anticipated advances in connection with the new satellite generation (EUMETSAT MTG). Our guests have been impressed by the variety of impactful activities the small ESSL team has undertaken over the past years, as documented by scientific posters and by the growing list of events, ranging from testbeds and seminars to expert workshops.

The official visit took place on 8 June 2023. The next day, a science journalist from the Austrian Broadcasting Corporation (ORF) visited our ESSL Research and Training Centre to interview participants and prepare a report on the EUMETSAT-ESSL Testbed and its importance for operational meteorologists in Europe. This week, participants from 15 different countries are taking part, from Ireland to Turkey, and from Portugal to Finland.

IF-Scale draft published for public commenting

ESSL and collaborators drafted a document on the “International Fujita Scale” (IF-Scale). It defines a new method to rate tornado and wind damage and was presented at the European Conference on Severe Storms in Bucharest, Romania, earlier this month.

The document is open for commenting until 31 May 2023. ESSL plans to implement the new scale in the European Severe Weather Database by 1 July 2023.

More information on the IF-Scale draft you can find here.

First ESSL Expert Workshop on Severe Weather Warnings: from Expectations via Physical Ingredients to Impact-based Warnings and Beyond

The workshop is scheduled for autumn, from 16 to 18 October 2023, and takes the very broad view. Target audience are forecasters (“warners”) and heads of forecasters, researchers and practicioners related to warnings, civil protection authorities, and end users of warnings (especially from critical infrastructure).

The following topics will be covered:

  1. The broad multidisciplinary view: risk ethics (philosophy, moral reasoning), human behaviour (psychology) and legal frameworks (just) in the context of the warning process
  2. Limitations and new prospects for ingredients-based warning approaches: How should the risk matrix be defined? Can more life be brought to forecasting impacts beyond the marketing term?
  3. Communication – dealing with uncertainty: Why is there so little progress in communicating the warning uncertainty, and how can this be improved?
  4. Action advice and public education: from understanding to response and action. We are seeking for good practice examples.
  5. General and tailored warnings: What are the necessary differences? And how can the gaps between warners, emergency managements and end users be best bridged?
  6. From physical ingredients to impact warnings: Are impacts in high-end meteorological events easier to predict and stronger tied to the physical magnitude than in more frequent and modest events?
  7. A critical moment in the meteorological sphere: transition from forecasting to nowcasting and the resulting potential sudden jump in probability of extremely rare events. Should there be a stronger focus on the warning means in the “last hour”? When in time and at which probability and intensity threshold should sirens and other “strongly interrupting and potentially also frightening” means of warning be used?
  8. Cross-institutional and cross-border communication: What is needed to ensure the flow of relevant information in extremely time-critical and high workload situations?

A detailled invitation can be downloaded here (PDF).

ECSS: Registration open and programme published

The registration for the 11th European Conference on Severe Storms is open and normal registration fees apply until 7 April. Starting 8 April, late registration fees do apply.

Please register here for on-site participation or online streaming (remote presentations are not foreseen).

General information on the ECSS including the scientific and social programme can be found here.

ESSL-EUMETSAT annual forecaster event

Online webinar: 20 April 2023, 12:00 to 14:30 UTC
Free of cost. Targeted to forecasters in nowcasting and warning operations.

We present and discuss MTG-related news relevant to forecasters: 

  • The current status of the MTG commissioning (Stephan Bojinski, EUMETSAT)
  • The ESSL Testbed 2022 in retrospect and lessons learned from expert workshops (Alois Holzer, ESSL)
  • Testimonial from a forecaster who participated in the ESSL Testbed 2022
  • Interesting cases from 2022 revisited (Tomas Pucik, ESSL) 

Please register for the webinar here:

https://events.teams.microsoft.com/event/517ea179-3349-405b-92ac-1a7cb04faa93@df7e8a07-a3fd-42a8-b745-17aa52648828

This webinar features key 2022 results from the joint ESSL-EUMETSAT activity introducing MTG data to operational weather forecasters in Europe. ESSL trainers describe highlights of severe convective weather cases that were analysed by forecasters during the testbeds in Wiener Neutstadt. Forecasters provide testimonials on their testbed experience and the importance of satellite products in the forecasting process. In addition, the ESSL expert workshops put the spotlight on novel MTG products such as the 0.9um FCI channel to detect low-level moisture, or the Lightning imager. The audience will learn about key take-aways from these workshops, for later use in training on MTG for all users.

Nikolai Dotzek Award 2023 to Pao Wang, Martin Setvák and Kris Bedka

The Nikolai Dotzek Award goes to three meteorologists with focus on satellite studies. The most prestigious award in the global severe weather research community is presented every second year in the memory of ESSL’s founding father, Dr. Nikolai Dotzek, for an outstanding contribution to the science of severe storms.

As the new generation of satellites in Europe, the United States, and Japan have been launched, their increased capabilities in terms of available channels and resolution will allow for better nowcasting of severe convective storms. It is a good time to acknowledge those who have contributed significantly to our understanding of the processes that occur on top of the convective storms, how they relate to storm severity, and how they can be operationally detected. ESSL presents the 2023 Nikolai Dotzek Award to three scientists who have strongly pushed satellite meteorology forward.

Pao Wang

The first awardee is Prof. Pao-Kuan Wang, who has used very high-resolution cloud models to simulate the processes at the top of convective storms. Simulations showed that overshooting tops act as obstacles to the anvil-relative wind. Thus, most of the storm top features that we observe from a satellite, such as cold rings, cold-Us, above-anvil cirrus plumes, storm-top gravity waves or ship wave patterns result from the interaction between overshooting tops and the ambient flow. Wang has also shown that some of these features result from internal gravity wave breaking processes, consequently contributing to lower stratospheric moistening. Wang was, until recently, director of the Research Center for Environmental Changes of the Academia Sinica and formerly professor at the University of Wisconsin in Madison.

Numerical simulation of a supercell showing the development of above-anvil cirrus plume as an example work of Pao Wang.

Martin Setvák

The second awardee is Dr. Martin Setvák, who in the late 1980’s described various forms of increased 3.7 micron cloud top reflectivity of convective storms and discussed its possible link to storm severity and updraft strength. Later he elaborated this concept with Dr. Charles A. Doswell. Together with Dr. Vincenzo Levizanni, Setvák formulated a concept of above-anvil cirrus plumes above convective storms on satellite imagery. He also contributed to the categorization of various storm-top phenomena, such as cold rings, closely collaborating on these topics with Prof. Pao K. Wang. Setvák is the father of the so-called “sandwich imagery”, a combination of infrared and visible channels, which is now in widespread use across the world. Martin Setvák has formally retired but still works part-time at the Czech Hydrometeorological Institute (CHMI).

NOAA-9 AVHRR imagery of an extremely severe hailstorm on 18 August 1986 over central Czechia clearly shows an above-anvil cirrus plume. This was one of the first storms of which the presence of the plume was noted by Martin Setvák.

Kris Bedka

The third awardee is Kristopher Bedka, who together with his team made significant strides toward the automation of the detection of both overshooting tops and above-anvil cirrus plumes. Using large records of these phenomena and their properties, Bedka investigated their statistical relationships with severe weather beneath them. His recent work concentrated on the automatic detection of high ice water content in deep convective storms, adversely impacting aircraft engine and air probe performance. He demonstrated the utility of 1-min super rapid scanning for analysis of satellite-observed cloud properties. His ongoing work expands towards wind profiling with an airborne doppler aerosol lidar – to only mention one of several fields of activity – and offers great promises for nowcasting and improving severe storms climatologies. Kris Bedka is affiliated with the NASA Langley Research Center.

An example from Kris Bedka’s work: Above-anvil cirrus plumes at the top of severe convective storms over Argentina on 8 February 2018. The northern one produced hail exceeding 18 cm.

The Nikolai Dotzek Award trophy represents a massive hailstone. The prize money is 1000 EUR together with an invitation to the European Conference on Severe Storms (ECSS). The award was instigated by the European Severe Storms Laboratory (ESSL) in 2011. The handing over of the award trophy usually crowns the dinner of the ECSS conference and will take place this year in Bucharest, Romania, on the 10th of May. 

Nikolai Dotzek Award trophy

The ESSL aims to contribute to the preparedness of European society for the impacts of severe storms by advancing scientific understanding, building human capacity, and fostering cooperation within Europe in this field.

ESSL provides training to forecasters, scientists, and policymakers on topics related to convective weather. ESSL participates in research projects and organizes the European Conference on Severe Storms to improve and stimulate the exchange of knowledge on severe convection. ESSL aims to establish and maintain close relationships with national weather services and research institutes to strengthen pan-European collaborations. ESSL maintains the European Severe Weather Database, to support research based on observations of severe convective weather or any related impact.

You can download a PDF document of this content here.

More information on the Nikolai Dotzek Award can be found here.

Major hailstorms of 2022

The year 2022 was another record-breaking year for hailstorms in Europe. In total, 8224 large hail reports (≥ 2 cm in diameter) were submitted to ESWD. That is 2791 more than in 2021, which was already a record-breaking year. Very large hail (diameter ≥ 5 cm) was reported 1334 times and 18 reports involved giant hail with a diameter ≥ 10 cm. There were 213 days with at least one large hail and 94 days with at least one very large hail report. The period of 20 May to 10 July was particularly active concerning very large hail. Out of 52 days, very large hail was observed on 42 of them.

Large hail reports in Europe in 2022 based on the European Severe Weather Database.

By far the largest number of reports was submitted for France (2461), followed by Italy (993) and Germany (583). The three days with the most hail reports were 4 June (411 reports), 20 June (385 reports), and 25 May (334 reports). Hail injured 215 people and killed 1. The two most societally impactful events were the Casamassima (Italy) hailstorm on 19 August with 100 injuries and the La Bisbal d’Empordà (Catalonia) hailstorm on 30 August with 67 injuries and one fatality. Hailstorms had a very large economic impact, especially in France, where the insured losses reached 4.8 billion € according to Swiss-Re. While some of the hailstorms produced large hail only for 15 minutes, some lasted for more than 3 hours. The longest-lasting hailstorm occurred on 22 May in France, producing large hail for 5 hours in a hail swath over 300 km long.

Major hail events of 2022 formed in a large range of CAPE and shear values. That said, the majority of the events occurred with CAPE exceeding 1000 J/kg and 0-6 km bulk shear exceeding 15 m/s, which is a parameter space where the large hail typically occurs. Some of the giant hail-producing events had a rather unremarkable environment. A good example of such a case is the hailstorm of 1 July over Czechia, which produced hail up to 11 cm in diameter with CAPE around 1000 J/kg and 0-6 km bulk shear well below 20 m/s. Giant hail was produced briefly following the merger of two storms. Hail around 3 cm in diameter was observed pre-merger and no large hail followed the brief period of giant hail production. This shows the importance of storm-scale processes, which can’t be captured by looking at the large-scale environment. 

Major hailstorms of 2022 in CAPE and 0-6 km bulk shear parameter space based on the ECMWF data. Background colors represent the relative frequency of hail > 2 cm acquired from the additive logistic regression model ARCHaMo for large hail (Battaglioli et al. 2023, submitted).

The biggest hailstorm cases of 2022:

20 May: Several hailstorms impacted northern France and western Germany. The largest hail, 8 cm across, fell in Sedan, France. Most hail damage was produced by a hailstorm that passed the northern suburbs of Koblenz, Germany, damaging roofs, windows, and cars. The largest hail reached 6 cm there.  

22 May: A supercell tracked for more than 300 km across west-central France, impacting the towns of Niort, Poitiers, Chauvigny, and Chateauroux. Supercell produced hail for 5 hours with several peaks of activity, when the hail diameter exceeded 8 cm in diameter. The largest measured hail was 12 cm in diameter, but even larger may have fallen with reports of weight up to 780 g. Chateauroux was hard hit with hailstones up to 9 cm in diameter. 4 people were injured and the hail badly damaged 250 houses and 1000 cars. 

One of the giant hailstones that fell on 22 May in France.
Source: https://www.francebleu.fr/infos/faits-divers-justice/en-images-a-frontenay-rohan-rohan-des-grelons-comme-des-oranges-1653307396

25 May: Several supercells produced long hail swaths over southeastern Austria, Slovenia, northeastern Croatia, and Hungary. The largest hail measured 8 cm in diameter. Severe damage to buildings was reported in Kapela Podravska, Croatia, and Kiskorpád, Hungary.

28 May: South-moving hailstorm produced damage east of Milan. The largest hail reached 7 cm in diameter. A hail up to 8.5 cm in diameter was reported in the Smolan region, Bulgaria, damaging cars, roofs, and agriculture. 

29 May: A woman was injured by very large hail in Italy. Hail up to 7.5 cm in diameter caused significant damage to roofs, cars, and greenhouses in Orizari, Bulgaria.

2 June: Severe hailstorms impacted southeastern Austria, Slovenia, and northern Croatia. Damage to crops, houses, and cars was reported. The maximum hail size reached “only” 5 cm, but hail fell in large quantities and was accompanied by severe winds in many locations with drifts up to 20 cm deep. 

3 June: Hailstorms affected southern France. The largest hail measured 7.5 cm in diameter and the longest hailstreak was 150 km long.

4 June:  Widespread hail damage was reported in central France, particularly in Vichy and surrounding areas. Hail reached up to 10 cm in diameter, severely damaging cars, roofs, and agriculture. 1 person was injured by hail in Vichy.

5 June: Hailstorms impacted eastern France, Switzerland, northwestern Italy, Slovenia, Austria, and Serbia. Hail up to 9.5 cm was reported in Frankolov, Slovenia, and an 11 cm hailstone fell in Kufstein, Austria.

19 June: A long-lived, right-moving supercell produced an almost 350 km long hail swath across France, affecting the outskirts of Orléans. The supercell produced hail for 4 hours. Roofs and cars were damaged along the path of the storm and the largest hail, measuring 8.5 cm, fell in Chambord and Saint Cyr en Val.

20 June: A long-tracked supercell crossed northern Bordeaux and destroyed more than 5000 hectares of agriculture with wind-driven hail in Dordogne. The largest hail diameter reached 7 cm. Serious damage to roofs and cars was reported in some parts of the hail swath. North of Pyrennees, a hailstorm produced giant hail with a maximum estimated hail size of 13 cm in Vic en Bigorre with widespread damage to roofs and cars. Long-lived supercells with hail also affected southern Germany and southeastern Czechia, but hail did not reach 5 cm. 

21 June: Third day of severe hailstorms in France in a row. Wind-driven hail up to 9 cm in diameter impacts regions of Auvergne and Bourgogne, destroying agriculture, roofs, windows, and cars. House facades and sides of cars suffered extensive damage as the hail was blown horizontally in the strong wind. A video showing the combination of severe winds and very large hail can be found here. Another long-lived supercell produced hail up to 8 cm, severely damaging roofs and cars in the region of Morvan. Very large hail also fell in Italy, Slovenia and Serbia. In Serbia, hail up to 7 cm in diameter caused severe damage to agriculture and roofs in the Moravički region.

Damage to the vehicles by the wind-driven hail in Digoin, France. Photo taken by
Christophe Asselin (Chroniques Chaotiques).
Damage to the vehicles by the wind-driven hail in Digoin, France. Photo taken by Christophe Asselin (Chroniques Chaotiques).

23 June: Hail and windstorm impacted Podgorica, Montenegro with damage to agriculture and cars. Largest hailstones reached 5.5 cm. Hail up to 8 cm in diameter was observed in Sfélinos, northern Greece.

26 June: Severe hailstorms affected eastern France with hail up to 7 cm in diameter. One of the storms also impacted Strassbourg and its outskirts and many cars were damaged.

27 June: Very large hail up to 8 cm in diameter was reported from southern Germany as two supercells tracked along the northern edge of the Alps. 7 cm hail was reported in western Czechia.

28 June: 1 person was injured by very large hail in Kastoriá, Greece.

29 June: Widespread large to very large hail was reported in eastern Czechia and southern Poland.

30 June: Very large hail fell in France, Italy, northern Czechia, Poland, and Bosnia-Herzegovina. The largest hail, 8.5 cm across, was reported in Blamont, France.

1 July: Giant hail up to 11 cm in diameter fell in Rovensko pod Troskami, Czechia. Very large hail also fell in eastern Czechia and western Slovakia from two long-lived supercells. Splitting supercells produced hail up to 6 cm in diameter in the Veneto region, Italy. 

5 July: Severe hailstorm impacted southwestern Serbia. Hail up to 7 cm in diameter damaged crops, roofs and cars. 

4 July: Very large hail up to 6 cm in diameter injured 2 in Castel Maggiore.

7 July: Several supercells formed in Veneto, Lombardia, and Emilia-Romagna regions in Italy, each producing very large hail. Widespread damage to cars, windows, and roofs was reported. The largest hail fell in Ostiglia and was estimated to be 9 cm in diameter. 

Very large hail that fell in Revere-Ostiglia area on 7 July. Photo taken by Luca Vezzosi.

20 July: Severe hailstorms occurred in Switzerland and eastern France. The most severe storm affected the region of Franche-Comté and the commune of Doubs, where hundreds of roofs, windows, and vehicles were badly damaged. The largest hailstone fell in Le Russey, estimated at 9 cm across. 

27 July: Very large hail was reported from the Abruzzo province in Italy. The largest hail, 9 cm in diameter, fell in Teramo and Ascoli Piceno. Damage to cars, roofs, and windows occurred. 

28 July: Left-moving supercell produced very large hail up to 8 cm in diameter near Lleida, Spain, damaging roofs, cars, windows, and greenhouses.  

13 August: Southward moving supercell produced a long hail swath across Sardegna, a rather rare occurrence on the island. The largest hail was estimated to be 9 cm in diameter and fell in Alà dei Sardi.

17 August: Widespread large to very large hail was reported from southern France. The largest hail fell in Bonnétage, estimated at 8 cm across. In Catalonia, a woman was slightly injured by a 5 cm hailstone. 

18 August: The event known especially for the powerful derecho producing wind gusts exceeding 60 m/s over Corsica also featured a number of damaging hailstorms. In the early morning hours, wind-driven hail injured 22 people in Sestri Levante and Lavagna in Liguria, Italy. Hail damaged cars, windows, and facades of houses. Around noon, a hailstorm struck Menorca with hail up to 7 cm in diameter. In the evening hours, another series of hailstorms impacted Italy, especially the regions of Marche and Tuscany. The largest hail, 11 cm in diameter, fell in Macerata Feltria damaging cars, and roofs and injuring 1 person.

19 August: Giant hail, reaching 10 cm in diameter, was reported from Casamassima, damaging cars, and windows. At least 100 people were lightly injured by hail. Most of the injuries were inflicted by broken glass. The number of injuries ranks as the third highest recorded in the ESWD for large hail events. 

Very large hail that fell on 19 August in Italy. Photo taken by Michele Connena.  

30 August: In the late afternoon, a supercell storm formed over the eastern Pyrenees. The storm moved southeastward and entered the district of Girona in Catalonia, producing a swath of very large hail (≥ 5 cm) between Esponnellá and Tamariu. Multiple reports of hailstones larger than 10 cm in diameter were collected with the largest stones estimated to be 12 cm. Impressive videos of the hailfall can be found here or here. Besides serious damage to roofs and cars, 67 injuries and even one fatality (a 2-month-old baby) resulted in the town of La Bisbal d’Empordà. 28 people had to be taken to the hospital, including one serious head injury. This was the first direct hail fatality in Europe since 1997. Furthermore, the number of injuries ranks as the fourth highest recorded in the ESWD for large hail events.

Giant hailstone that fell in Catalonia on 30 August 2022. 
Source: https://mobile.twitter.com/Supercelulas

8 September: Southeastward moving supercell over Lazio, Italy produced a swath of very large hail. The largest hail, 9 cm across, fell in Boville Ernica.

27 September: Serious hail damage to roofs, cars, windows, and greenhouses was reported from Serbia, especially in Pomoravski okrug region. Hail reached up to 6 cm in diameter.

23 October: Intense storm that resulted in a long-tracked tornado in Haute-Normandie, northwestern France also produced very large hail up to 7.5 cm in diameter.