Wikipedia

Cyclone Lothar

Cyclone Lothar[1] is regarded as the worst European windstorm recorded during the 20th century.[2] Crossing France, Belgium, Luxembourg and Germany between 25 December and 27 December 1999, Cyclone Lothar's average winds reached up to 115 km/h inland (Orly), but with gusts exceeding 150 km/h, almost equivalent to a Category 2 hurricane,[3][a] resulting in 110 deaths (including 88 in France alone)[6] and more than €15 billion in damage, becoming the costliest European windstorm ever recorded.[2]

Cyclone Lothar
Track of the central low pressure of Lothar
Meteorological history
Formed25 December 1999
Dissipated27 December 1999
Extratropical cyclone
Highest gusts259 km/h (161 mph)
Lowest pressure960 hPa (mbar); 28.35 inHg
Overall effects
Fatalities110
Damage€15 billion (1999)
Areas affectedWestern Europe
Part of the 1999–2000 European windstorm season

Lothar moved at 100 km/h along an axis from Brittany (about 4 am) to Lorraine (about 9 am) to Alsace (11 am) with a front 150 km wide.[3] It was the second of a series of devastating European windstorms which made landfall in December 1999,[7][8] occurring around three weeks after Cyclone Anatol, which caused severe damage in Denmark and nearby parts of Sweden and Germany. The day after Lothar moved over western Europe, another intense European windstorm, Cyclone Martin, caused severe damage to the south of Lothar's track.

Meteorological history

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A series of severe winter storms crossed the North Atlantic and Western Europe in December 1999. In early December, Denmark was hit by Cyclone Anatol which caused severe damage there and in neighboring areas. A second storm then crossed Europe on 12 December.[9] Starting on December 20, 1999, the Iceland depression strengthened and created a strong temperature contrast along a polar front across the Atlantic. Meanwhile, a high-pressure system covered Central and Eastern Europe. A very deep and sizable depression moved across Britain on the night of 24–25 December (analysed to have possibly reached a low of 938 mb between Scotland and Norway),[10] this set up a large area of westerly flow into Europe which brought Lothar. This highly unstable situation inevitably meant low predictability, and saw an unusually straight and strong jet stream (similar circumstances were also noted the day before the arrival of the Great Storm of 1987).[11]

Lothar moved rapidly, pushed by a strong jet stream on the morning of December 26, at a speed close to 130 km/h.[8] It reached a central pressure of 985 hPa about 300 km south of Ireland. As it approached the northwest coast of France, the storm slowed to 97 km/h before beginning a rapid intensification phase. The central pressure dropped by 32 hPa in 8 hours, falling to 960 hPa during the storm's passage over Paris, which corresponds to the definition of a meteorological bomb.[6][12] Its deepening intensified on land due to strong interaction with the high-altitude jet stream, which was close to 400 km/h at 9,000 m altitude.[8][6]

Lothar was extremely intense and only 300 km in diameter, much smaller than the typical diameter for a mid-latitude depression.[8] Its rapid intensification generated an internal pressure gradient comparable to what is observed in Category 2 hurricanes. Exceptionally strong winds were recorded in an area 150 km south of the depression's center.[8]

Before Lothar dissipated, a new disturbance formed near where Lothar had formed. This storm, called Martin, followed a path 200 km south of Lothar and reached its recorded minimum pressure of 964 hPa. Its winds were at maximum intensity as it approached the French coast on the evening of December 27, comparable to those of Lothar: 190 km/h on the coasts and 158 km/h inland.[8]

Storm Martin then struck France and central Europe from 26 to 28 December 1999. At the end of January 2000 two additional damaging storms crossed Denmark and the northern part of Germany.[9]

Forecast

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See also: Great storm of 1987 and Cyclone Martin (1999)
 
Cyclones Lothar (L) and Martin (M) viewed by satellite, December 26, 1999.

After the problems of the great storm of 1987, European meteorological services greatly improved their numerical weather prediction models, and Météo-France predicted Lothar. However, cyclone Lothar was not well predicted, with one meteorologist later claiming that forecasts could be split into those that were poor and those that were very poor.[11]

According to some forecasts, the storm was predicted to pass through the United Kingdom, while others failed to predict significant intensification at all.[8] The strong jet stream that was the chief cause of the instability was well predicted by the European Centre for Medium-Range Weather Forecasts 9 days earlier.[11] Approximately 24 hours before the storm hit France, Météo-France issued a warning of a strong storm with the correct path, but two hours before the storm hit Paris, inland windspeeds were still predicted to be between 90 and 130 km/h (56 and 81 mph), rather than the 125–175 km/h (78–109 mph) range actually experienced.[11] After the storm, forecasters wondered if additional coastal data could have improved predictions or if the dramatic development of this storm exceeded the capabilities of operational numerical weather prediction models.[8]

MeteoSwiss found the storm Lothar extremely difficult to predict, as even the large forecast models of international weather services initially overlooked the small disturbance above the Atlantic Ocean which formed the storm. Consequently, the power and extent of the storm was only recognized in the early morning of 26 December, which resulted in shorter warning times in Switzerland.[9] In a number of places, officials failed to realize the importance of the warnings, so they were not passed on to the public as they should have been. It is presumed that this occurred because of the holidays.[9]

The German Weather Service (Deutscher Wetterdienst) was criticised for not issuing a storm warning for Lothar in contrast to the weather services of other countries and private German services, apparently due to a software bug.[citation needed]

Lothar successor

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A case study of the Manual of Synoptic Satellite Meteorology featured by the Austrian Meteorological Institute (ZAMG) identified an area of secondary cyclogenesis which brought gusts in excess of 90 km/h to Northern France, Belgium and Southwestern Germany.[13] The system formed in the wake of Lothar, and crossed Europe before the arrival of the later Cyclone Martin. The identification of this secondary area and its frontal systems contrasts with the analysis of the German Weather Service which suggested that solely a 'trough line' crossed Germany.[14]

Highest winds

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Recorded winds during Lothar, according to the meteorological services of the countries mentioned:

Country Place Speed Country Place Speed
France[15][16][17][18] Ploumanac'h 148 km/h (92 mph) Switzerland[19][20] La Chaux-de-Fonds 134.6 km/h (83.6 mph)
Île de Groix 162 km/h (101 mph) Chasseral 177.5 km/h (110.3 mph)
Rennes 126 km/h (78 mph) La Dôle 201.2 km/h (125.0 mph)
Nantes 126 km/h (78 mph) Geneva 103.7 km/h (64.4 mph)
Alençon 166 km/h (103 mph) Col du Grand-Saint-Bernard 178.6 km/h (111.0 mph)
Rouen 140 km/h (87 mph) Évolène 124.6 km/h (77.4 mph)
Chartres 144 km/h (89 mph) Lucerne 141.5 km/h (87.9 mph)
Paris (Parc Montsouris) 169 km/h (105 mph) Zürich 157.8 km/h (98.1 mph)
Paris Eiffel Tower >216 km/h (134 mph) Schaffhausen 162 km/h (101 mph)
Orly 173 km/h (107 mph) Säntis 229.7 km/h (142.7 mph)
Dijon 126 km/h (78 mph) Germany[21][4] Weinbiet 184 km/h (114 mph)
Metz 155 km/h (96 mph) Stuttgart 144 km/h (89 mph)
Nancy 144 km/h (89 mph) Karlsruhe 151 km/h (94 mph)
Colmar 165 km/h (103 mph) Grosser Arber 162 km/h (101 mph)
Strasbourg 144 km/h (89 mph) Hohentwiel 272 km/h (169 mph)

Impact

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During Cyclone Lothar, wind speeds reached around 150 km/h (93 mph) in low-lying areas and more than 250 km/h (160 mph) on some mountains. In less than half a day the storm tore across France, Belgium and Germany, only finally beginning to weaken as it crossed Poland. The storm's compact internal pressure gradients generated winds which were comparable to those of a Category 2 hurricane.[6]

The Paris region was strongly affected by the storm during the early morning. The Palace of Versailles and its monumental park were considerably damaged (over 10,000 trees were lost within two hours, including valuable specimens planted by Napoleon and Marie Antoinette). Other cultural heritage, forests and public gardens throughout the area were as severely affected by the hurricane-force winds. In Paris, more than 60% of buildings suffered roof damage; in other settlements across northern France, the total approached 80%.[2] Public life was disrupted due to power outages and blocked infrastructure. Besides buildings and infrastructure, forests, such as the Black Forest in Germany, suffered major damage resulting in substantial economic loss.

Lothar and Martin together left 3.4 million customers in France without electricity, and forced Électricité de France to acquire all the available portable power generators in Europe, with some even being brought in from Canada.[22] These storms brought down a quarter of France's high-tension transmission lines and 300 high-voltage transmission pylons were toppled, including 100 during Cyclone Lothar. It was one of the greatest energy disruptions ever experienced by a modern developed country.[6]

Damage

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Insurers and authorities in the affected countries reported that 110 victims total were identified:[6]

Nationality Deaths
France[23] 53
Switzerland 29
Germany[23] 17
  • Economic losses were estimated at 5.9 billion euros (1999).[6]
  • Trees knocked down:[24][25]
    • Baden-Württemberg in Germany: 25 million cubic meters.
    • France: The damage caused by the Martin and Lothar storms that occurred in late December 1999 is indistinguishable. It is estimated that the combined impact of both systems resulted in the destruction of 115 to 140 million cubic meters of wood, which is comparable to the volume carried by an uninterrupted train convoy from Oslo to Gibraltar.
    • Switzerland: 13 million cubic meters of wood.

Lothar is the strongest windstorm on record in Europe since reliable meteorological records have been kept.[26] In terms of comparable events, the Great Storm of 1703 is the closest precedent. This occurred on December 7 and 8, 1703, in Brittany and southern England, resulting in over 8,500 casualties.[27]

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    Windthrow in a forest in Arenbachtal, Baden-Württemberg, after the storm.
  •  
    Clearing work in a windthrow area in the Black Forest near Baden-Baden.
  •  
    Parcel of Douglas fir trees felled by the storm Lothar on December 26, 1999, in the forest of Fréteval, Loir-et-Cher, France.

See also

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  • Other European windstorms which brought prolonged high winds to urban areas:

Notes

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  1. ^ Gusts reached 180 km/h on the plains of Saint-Sylvain and up to 259 km/h (on Mount Wendelstein in the Bavarian Alps)[4] and 272 km/h (on Mount Hohentwiel north of Lake Constance in Baden-Württemberg)[5] at higher altitudes.

References

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  1. ^ "1999 Windstorm naming lists". FU-Berlin. January 2000. Archived from the original on 7 September 2017. Retrieved 9 December 2011.
  2. ^ a b c "Christmas 20 years ago: Storms Lothar and Martin wreak havoc across Europe". Swiss Re. Swiss Re Group. Retrieved 12 October 2020.
  3. ^ a b "Une situation météorologique exceptionnelle". Tempêtes de décembre 1999. Archived from the original on 2016-03-04. Retrieved 4 August 2016.
  4. ^ a b "Bewertung der Orkanwetterlage am 26.12.1999 aus klimatologischer Sicht" (PDF). Deutscher Wetterdienst (in German). Retrieved 9 January 2016.
  5. ^ "Wetterextreme". unwetterzentrale.de (in German). Retrieved 26 May 2015.
  6. ^ a b c d e f g Tatge, Yörn. "Looking Back, Looking Forward: Anatol, Lothar and Martin Ten Years Later". Air-Worldwide. Retrieved 30 May 2013.
  7. ^ "Three extreme storms over Europe in December 1999". Université de Cologne. 2001. Archived from the original on 2012-03-02.
  8. ^ a b c d e f g h "Les tempêtes Lothar et Martin" (PDF). Risk management Solutions (RMS). Retrieved 15 March 2015.
  9. ^ a b c d Brüdl, M.; Rickli, C. (2002). "The storm Lothar 1999 in Switzerland – an incident analysis" (PDF). Forest Snow and Landscape Research. 77: 207–216. Archived from the original (PDF) on 28 April 2015. Retrieved 1 June 2013.
  10. ^ Brown, Paul R. (February 2000). "A brief note on the intense depressions of late December 1999 over Western Europe" (PDF). Journal of Meteorology. 25. Retrieved 13 January 2017.
  11. ^ a b c d "Windstorms Lothar and Martin" (PDF). RMS Risk Management Solutions. Archived from the original (PDF) on 17 December 2013. Retrieved 31 May 2013.
  12. ^ "Lothar - 10 ans après". MétéoSuisse. 2009. Archived from the original on 2014-12-15. Retrieved 6 March 2015.
  13. ^ "Storm Catastrophe 25 - 28 December 1999 - Lothar and Lothar Successor". ZAMG. Retrieved 16 July 2013.
  14. ^ Welzenbach, F. (2010). "Phenomenological examination of 'Lothar Successor' - the forgotten storm after Christmas 1999" (PDF). Unknown. Archived from the original (PDF) on 29 May 2014. Retrieved 16 July 2013.
  15. ^ Baleste, Marie-Claire; Brunet, Hubert; Mougel, Alain. "Les tempêtes exceptionnelles de Noël 1999". Météo-France/ Direction de la Production. Bulletin climatique annuel. ISSN 1159-1056.
  16. ^ "Bulletin climatique" (PDF). Météo-France. 1999. Retrieved 16 March 2015.
  17. ^ "Aspects méthodologiques et historiques des tempêtes et des chablis".
  18. ^ "Lothar le 26 décembre 1999". Météo-France. Retrieved 28 January 2017.
  19. ^ "Cartes des vents lors de la tempête Lothar" (in French). Institut suisse de météorologie (ISM). Retrieved 2007-05-07.[dead link‍]
  20. ^ "Tempête d'ouest et températures record" (PDF).
  21. ^ "Rapports sur Lothar" (PDF) (in German). Deutscher Wetterdienst (German weather service). Retrieved 2007-05-07.
  22. ^ "Impacts of Severe Storms on Electric Grids" (PDF). Union of the Electricity Industry – EURELECTRIC. 2006. Archived from the original (PDF) on 21 September 2013. Retrieved 5 January 2013.
  23. ^ a b "Tempête du 26 décembre 1999".
  24. ^ Spicher, Michel (2004). "L'ouragan Lothar, un cataclysme dans le monde forestier". Site officiel du Canton de Fribourg. Retrieved 6 March 2015.
  25. ^ Denis, Michel (2004). "Expertise collective suite aux dégâts en forêt lors des tempêtes de décembre 1999". Archived from the original on 2006-02-19.
  26. ^ Hontarrède, M. (2000). "Les tempêtes jumelles de Noël 1999". Revue Met-Mar (187).
  27. ^ Chaboud, R. (1994). La météo, questions de temps (in French). Éditions Nathan. ISBN 9782092605400.
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Wikimedia Commons has media related to Lothar (storm).
  • Met Office, University of Exeter & University of Reading Extreme Wind Storm Catalogue: Lothar
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